Universal protocol for enabling a device to discover and utilize the services of another device

Abstract

A method and apparatus for enabling any of a variety of devices to communicate with each other over a common or universal protocol. In general, a client device and a server device communicate with each other over a communications link utilizes the common protocol. Initially, once a communications link is established, the server device identifies itself to the client device by sending a tag line message over the communications link. Upon receiving the tag line message, the client then determines that the server is capable of using the common protocol. The client device may then initiate several requests including a service request, a type request or a use request. If the client device initiates a service request, the client simple uses the common protocol to request the service. In response to receiving the service request, the server device performs the requested service and provides a confirmation to the client device. If the client device initiates a type request, the service device will respond by providing information regarding the services the server device provides and the device types supported by the server device. If the client device initiates a use request for a particular service, the server device will provide information to the client device that describes the necessary parameters for invoking the particular service.

Claims

What is claimed is:

1. A method of communicating between a client device and a server device over a communications link, the method comprising the steps of:

under control of a client device, initiating establishment of a link layer connection between the client device and a specified server device;

under control of the server device, establishing a data connection with the client device over the link layer connection by transmitting a tag line message to the client device that identifies a specified data protocol with which the server device is capable of communicating, the established data connection based on the specified data protocol; and

subsequent to the establishment of the data connection,

transmitting a service-command from the client device to the server device over the data connection, the service-command identifying a particular service to be performed by the server device; and

in response to receiving the service-command at the server device, initiating the requested service and transmitting a status-response to the client device over the data connection.

2. The method of claim 1 wherein the specified data protocol is SDTP.

3. The method of claim 1 further comprising, prior to the transmitting of the service-command, the steps of:

transmitting a type-command from the client device to the server device over the data connection, the type-command requesting the server device to provide service information identifying a set of services offered by the server device; and

in response to the type-command, transmitting the service information from the server device to the client device.

4. The method of claim 3 wherein the transmitting of the service information further comprises transmitting a plurality of device types supported by the server device.

5. The method of claim 1 further comprising, prior to the transmitting of the service-command, the steps of:

transmitting a use-command from the client device to the server device over the data connection, the use-command requesting the server device to provide use information describing how to invoke one of a set of services offered by the server device; and

in response to the use-command, transmitting the use information from the server device to the client device.

6. A device that is capable of communicating over a communications link with a plurality of server devices of a plurality of device types, the device comprising:

a communications link interface; and

a processing unit, the processing unit being operable to send and receive data over the communications link and being operable to, for each of the plurality of server devices:

establish a communicative connection between the device and the server device;

obtain service information over the communicative connection that identifies a set of services offered by the server device, wherein the obtaining of the service information by the device includes receiving a response to a type-command that was sent to the server device by the device; and

invoke one of the set of services offered by the server device.

7. The device of claim 6, wherein the processing unit is further operative to obtain use information over the communicative connection that identifies how to invoke a particular service of the set of services offered by the particular server device.

8. The device of claim 7 wherein the use information identifying how to invoke a service includes identifications of parameters used when invoking the service and of permissible values for the identified parameters.

9. The device of claim 6 wherein the processing unit is further operative to obtain supported device information over the communications link that identifies at least one type of device that is supported by the server device.

10. The device of claim 9 wherein at least some of the server devices each support multiple types of devices by emulating at least some of those multiple device types, and wherein the supported device information that is obtained by the device for those server devices identifies the multiple types of devices supported by those server devices.

11. A method by which a common data protocol is used to enable a first device of a first device type to communicate with a second device of a second device type over a first communications link, to enable the second device to communicate with a third device of a third device type over a second communications link, and to enable the third device to communicate with the first device over a third communications link, the first device and the second device together forming a first device pair, the second device and the third device together forming a second device pair, and the third device and the first device together forming a third device pair, wherein one of the devices in each of the first, second and third device pairs is a client device and the other of the devices in each of the first, second and third device pairs is a server device, the device pairs such that at least one of the devices is a client device in one device pair and is a server device in another device pair, the method comprising the steps of, for each device pair:

establishing a connection between the client device of the device pair and the server device of the device pair using a link protocol;

using the link protocol to establish communication between the client device and the server device using the common data protocol;

transmitting a type-command from the client device to the service device using the common data protocol, the type-command requesting the service device to provide service information identifying services offered by the server device; and

in response to the type-command, transmitting the service information from the server device to the client device.

12. The method of claim 11, further comprising the steps of:

transmitting a use-command from the client device of the device pair to the server device of the device pair using the common data protocol, the use-command requesting the server device to provide use information describing use of one of the services offered by the server device; and

in response to the use-command, transmitting the use information from the server device to the client device.

13. The method of claim 11, further comprising the steps of:

transmitting a service-command from the client device of the device pair to the server device of the device pair using the common data protocol, the service-command identifying a particular service to be performed by the server device; and

in response to the service-command, initiating the requested service and transmitting a status-message to the client.

14. A method for enabling a client device to communicate with a server device over a communications link, the method comprising the steps of:

establishing a communicative connection with the server device;

subsequent to establishing the communicative connection, transmitting a type-command to the server device, the type-command requesting the server device to provide service information defining a set of services offered by the server device;

receiving the service information; and

subsequent to receiving the service information, transmitting a service-command to the server device, the service-command identifying a particular service to be performed by the server device.

15. The method of claim 14, further comprising the steps of:

subsequent to establishing the communicative connection, transmitting a use-command to the server device, the use-command requesting the server device to provide use information defining the requirements for invoking one of a set of services offered by the server device; and

receiving the use information.

16. A method for enabling a server device to communicate with a client device over a communications link, the method comprising the steps of:

establishing a communications link with the client device;

receiving a type-command from the client device, the type-command requesting the server device to provide service information defining a set of services offered by the server device;

in response to receiving the type-command from the client device, transmitting the service information to the client device;

receiving a service-command identifying a particular service to be performed by the server device; and

initiating the requested service.

17. The method of claim 16, further comprising the steps of:

receiving a use-command from the client device, the use-command requesting the server device to provide use information defining the requirements for invoking one of a set of services offered by the server device; and

in response to receiving the use-command from the client device, transmitting the use information to the client device.

18. A device that is capable of communicating over a communications link with a plurality of server devices of a plurality of device types, the device comprising:

a communications link interface; and

a processing unit, the processing unit being operable to send and receive data over the communications link, being operative to obtain supported device information over the communications link that identifies at least one type of device that is supported by the server device, and being operable to, for each of the plurality of server devices:

establish a communicative connection between the device and the server device;

obtain service information over the communicative connection that identifies a set of services offered by the server device, wherein the obtaining of the supported device information by the device includes receiving a response to a type-command that was sent to the server device by the device; and

invoke one of the set of services offered by the server device.

19. A device that is capable of communicating over a communications link with a plurality of server devices of a plurality of device types, the device comprising:

a communications link interface; and

a processing unit, the processing unit being operable to send and receive data over the communications link, being operative to obtain use information over the communicative connection that identifies how to invoke a particular service of the set of services offered by the particular server device, and being operable to, for each of the plurality of server devices:

establish a communicative connection between the device and the server device;

obtain service information over the communicative connection that identifies a set of services offered by the server device, wherein the obtaining of the use information by the device includes receiving a response to a use-command that was sent to the server device by the device; and

invoke one of the set of services offered by the server device.

20. A method for enabling a client device to communicate with a server device over a communications link, the method comprising the steps of:

establishing a communicative connection with the server device;

after establishing the communicative connection, transmitting to the server device a use-command requesting the server device to provide use information that describes how to invoke a specified one of multiple services offered by the server device;

receiving the use information; and

after receiving the use information, transmitting a service-command to the server device requesting the server device to invoke the specified service, the service-command specified in a manner based on a description included in the received use information.

21. The method of claim 20 including, prior to the transmitting of the use-command to the server device, receiving service information from the server device that identifies the multiple services offered by the server device, and wherein the specified service is selected from the multiple services identified in the received service information.

22. The method of claim 21 wherein the service information is received from the server device in response to a prior type-command transmitted to the server device.

Description

TECHNICAL FIELD

This invention relates to the field of data transfer protocols and, more particularly, relates to simple data transfer protocols capable of being used to facilitate communication between a wide variety of consumer devices.

BACKGROUND

Data transfer protocols are used to facilitate communication between electronic devices by providing a common set of rules by which data may be exchanged between one device and another. A universal protocol could theoretically allow one device to communicate with any other device, from simple devices like the lights in a room to complex devices like personal computers. However, to approach such an ideal, the protocol itself has to be usable with at least a significant proportion of the devices. Different types of devices have different characteristics such as microprocessor abilities, free memory, and accompanying costs. In addition, consumer devices are produced by a wide variety of manufacturers. Coordination and cooperation in interfacing a wide variety of electronic devices is very difficult. Thus, the need exists for a universal protocol that may be implemented by a large variety of device types produced by various manufacturers.

Many times in the past, manufacturers have made attempts to allow consumer level devices to be able to communicate meaningful data or commands to one another. Many protocols define data links between standard small devices. However, this also meant that usually the "standard" became only a standard for that genre of device. Further, while these protocols provide a data link, they do not provide a standard method to allow simple relevant information transfer between two small devices. For example, a typical pager cannot send control information to any particular cellular telephone requesting the cellular telephone to initiate a call to a certain number; a "caller-ID" box is not able to instruct a PDA to display all the contact information for the person who is calling; and a PDA cannot print or fax (without a modem or special drivers). Thus, a need exists for a universal protocol which can provide a simple data link between a wide variety of devices.

SUMMARY

The present invention includes a protocol and a method for facilitating communication between various electronic devices and the sharing of features, functionality and information between these devices. In general, the present invention is directed towards a protocol by which one device (the "client device") can discover what services are offered by another device (the "server device"). Utilizing this protocol, the client device can take advantage of the services of the server device. Advantageously, the present invention is simple enough to be used by nearly any type of electronic device, but at the same time it is robust enough to allow a user to author high-level applications utilizing multiple different services available from multiple devices without requiring the user to have any knowledge of any particular device interface or how the device works. The present invention is capable of use by a wide range of devices including, but not limited to, pagers, cellular telephones, wired telephones, caller-ID ("CID") boxes, printers, facsimile machines, personal data assistant ("PDA"), personal computers, information sources, time pieces, stereo equipment, video equipment, thermostats, weather stations, doors, lights, and security systems. The present invention allows these devices to interact, by standardizing many of the normal tasks associated with these devices. Convergence Corporation, the assignee of the present invention, has developed a universal protocol, referred to as the Service Discovery Transport Protocol ("SDTP"), which embodies many of the aspects of this invention. Thus, embodiments of the present invention include a universal protocol that can be implement in a wide variety of device types produced by various manufacturers. In addition, embodiments of the present invention provide a simple data link between these devices.

The operation of a protocol implementing aspects of the present invention actually begins when the server device sends a message to the client device to inform the client device that it is capable of communicating using the protocol. In an exemplary embodiment, this message and all subsequent messages may be sent using standard 8-bit ASCII characters. Once the client device determines that the server device is capable of communicating using the protocol, the client device may request the server device to identify what kinds of services the server provides. This request is performed by transmitting a type-command to the server device.

Upon receiving the type-command, the server device responds by transmitting one or more device/service identifiers back to the client device. Each device/service identifier is unique, and represents either a specific device type, such as a thermostat, a door, a pager, a PDA or many others, or a specific service type, such as the ability to raise the temperature of the thermostat or to transmit the messages stored in the pager. Finally, the server device transmits a standard ASCII sequence to signal the last of the device/service identifiers.

After the server device identifies itself as being capable of using the protocol, the client device may issue commands to the server device using the unique service identifiers just described. Any necessary parameters may be passed along as well. If everything operates correctly, the service identified by the command is then provided by the server device. Finally, the server device responds to each such command by sending a status code back to the client device. The status code denotes that either: (a) the requested service was unavailable; (b) the server device was unable to complete the operation; (c) the command contained a syntax error; or (d) that the operation completed successfully.

The protocol also supports "learning" new services with which the client is not previously familiar. To invoke this capability, the client device transmits a use-command to the server device to identify the service that the client wishes to learn. Upon receiving the use-command, the server device transmits a service identifier corresponding to the new service and any available parameters. The client device may then invoke the service by sending the service identifier and the requisite parameters.

Another feature of the present invention is the ability to drop into a different, proprietary protocol. By issuing the native-command, the client device can instruct the server device to utilize the existing link to communicate in whatever proprietary protocol is utilized for that link.

Thus, the present invention includes at least four aspects. One aspect of the present invention is a protocol that allows a client device to request a server device to identify what services are provided by the server device and then allows the client device to request one or more of those services to be provided.

Another aspect of the present invention involves the ability of a client device to determine whether any of a wide variety of server devices are capable of communicating with the client device using a standard protocol and then commanding a particular device to carry out a particular function.

A third aspect of the present invention is the structure of the data packets that are transmitted by a server device to uniquely identify the device types emulated by the server device and the services the server device is capable of performing.

A fourth aspect of the invention involves the ability of a client device to determine whether a particular server device is capable of communicating using the SDTP protocol by first establishing communication using any appropriate technology and then determining if further communication is possible using SDTP.

Therefore, it can be seen that these aspects of the present invention may be utilized within a protocol, operable within a variety of device types, that facilitates communication between the variety of device types over a simple data link. These and other aspects, features, and advantages of the present invention will be set forth in the description that follows and possible embodiments thereof, and by reference to the appended drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram that illustrates an exemplary environment suitable for implementing various embodiments of the present invention.

FIG. 2 illustrates an exemplary environment in which the protocol of the present invention operates.

FIG. 3 is an exemplary sequential diagram showing the basic steps of the protocol of the present invention.

FIG. 4 is an exemplary sequential diagram showing the basic steps of the "learning" capability of the protocol of the present invention.

FIG. 5 is an exemplary sequential diagram showing how communication between a client device and a server device may be, switched from using the protocol of the present invention to a native, proprietary protocol.

FIG. 6 is a state diagram illustrating the operation of the protocol of the present invention in a client.

FIG. 7 is a state diagram illustrating the operation of the protocol of the present invention in a server.

DETAILED DESCRIPTION

Before describing the details of the current invention, some terminology used herein is described. The term "protocol" generally refers to a set of formal rules or conventions describing how data is treated in an electronic system. In electronic communications, protocols define the electrical and physical standards to be observed, such as bit-ordering and byte-ordering and the transmission and error detection and correction of the bit messages, the client-server dialog, character sets, and sequencing of messages. Link protocols define the basics of how communication is established and maintained between two devices. Data protocols define how meaningful data is exchanged between the two devices using the link protocol as the underlying communication layer. Unless otherwise indicated, the term "protocol," as used below, refers to the data protocol employed by a given connection between two devices to communicate meaningful data, such as the discovery of information about one device and the issuance of commands by one device to the other.

Referring now to the drawings, in which like numerals represent like elements throughout the several figures, aspects of the present invention and exemplary operating environments will be described.

FIG. 1 is a system diagram that illustrates an exemplary environment suitable for implementing various embodiments of the present invention. FIG. 1 and the following discussion provide a general overview of a platform onto which the invention may be integrated or implemented. Although in the context of the exemplary environment the invention will be described as consisting of instructions within a software program being executed by a processing unit, those skilled in the art will understand that portions of the invention, or the entire invention itself, may also be implemented by using hardware components, state machines, or a combination of any of these techniques. In addition, a software program implementing an embodiment of the invention may run as a stand-alone program or as a software module, routine, or function call, operating in conjunction with an operating system, another program, system call, interrupt routine, library routine, or the like. The term program module will be used to refer to software programs, routines, functions, macros, data, data structures, or any set of machine readable instructions or object code, or software instructions that can be compiled into such, and executed by a processing unit.

Those skilled in the art will appreciate that the system illustrated in FIG. 1 may take on many forms and may be directed towards performing a variety of functions. Examples of such forms and functions include mainframe computers, mini computers, servers, work stations, personal computers, hand-held devices such a personal data assistants and calculators, consumer electronics, note-book computers, lap-top computers, and a variety of other applications, each of which may serve as an exemplary environment for embodiments of the present invention. The invention may also be practiced in a distributed computing environment where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

The exemplary system illustrated in FIG. 1 includes a computing device 10 that is made up of various components including, but not limited to, a processing unit 12, non-volatile memory 14, volatile memory 16, and a system bus 18 that couples the non-volatile memory 14 and volatile memory 16 to the processing unit 12. The non-volatile memory 14 may include a variety of memory types including, but not limited to, read only memory (ROM), electronically erasable read only memory (EEROM), electronically erasable and programmable read only memory (EEPROM), electronically programmable read only memory (EPROM), electronically alterable read only memory (EAROM), and battery backed random access memory (RAM). The non-volatile memory 14 provides storage for power on and reset routines (bootstrap routines) that are invoked upon applying power or resetting the computing device 10. In some configurations the non-volatile memory 14 provides the basic input/output system (BIOS) routines that are utilized to perform the transfer of information between the various components of the computing device 10.

The volatile memory 16 may include a variety of memory types and devices including, but not limited to, random access memory (RAM), dynamic random access memory (DRAM), FLASH memory, EEROM, bubble memory, registers, or the like. The volatile memory 16 provides temporary storage for program modules or data that are being or may be executed by, or are being accessed or modified by the processing unit 12. In general, the distinction between non-volatile memory 14 and volatile memory 16 is that when power is removed from the computing device 10 and then reapplied, the contents of the non-volatile memory 14 is not lost, whereas the contents of the volatile memory 16 is lost, corrupted, or erased.

The computing device 10 may access one or more external display devices 30 such as a CRT monitor, LCD panel, LED panel, electro-luminescent panel, or other display device, for the purpose of providing information or computing results to a user. The processing unit 12 interfaces to each display device 30 through a video interface 20 coupled to the processing unit over system bus 18.

The computing device 10 may have access to one or more external storage devices 32 such as a hard disk drive, a magnetic disk drive for the purpose of reading from or writing to a removable disk, and an optical disk drive for the purpose of reading a CD-ROM disk or to read from or write to other optical media, as well as devices for reading from and or writing to other media types including but not limited to, FLASH memory cards, Bernoulli drives, magnetic cassettes, magnetic tapes, or the like. The processing unit 12 interfaces to each storage device 32 through a storage interface 22 coupled to the processing unit 12 over system bus 18. The storage devices 32 provide non-volatile storage for the computing device 10.

The computing device 10 may receive input or commands from one or more input devices 34 such as a keyboard, pointing device, mouse, modem, RF or infrared receiver, microphone, joystick, track ball, light pen, game pad, scanner, camera, or the like. The processing unit 12 interfaces to each input device 34 through an input interface 24 coupled to the processing unit 12 over system bus 18. The input interface may include one or more of a variety of interfaces, including but not limited to, an RS-232 serial port interface or other serial port interface, a parallel port interface, a universal serial bus (USB), an optical interface such as infrared or IRDA, an RF or wireless interface such as Bluetooth, or other interface.

The computing device 10 may send output information, in addition to the display 30, to one or more output devices 36 such as a speaker, modem, printer, plotter, facsimile machine, RF or infrared transmitter, or any other of a variety of devices that can be controlled by the computing device 10. The processing unit 12 interfaces to each output device 36 through an output interface 26 coupled to the processing unit 12 over system bus 18. The output interface may include one or more of a variety of interfaces, including but not limited to, an RS-232 serial port interface or other serial port interface, a parallel port interface, a universal serial bus (USB), an optical interface such as infrared or IRDA, an RF or wireless interface such as Bluetooth, or other interface.

The computing device 10 may operate in a networked environment using logical connections to one or more remote systems, such as a remote computer 38. The remote computer 38 may be a server, a router, a peer device or other common network node, and typically includes many or all of the components described relative to the computing device 10. When used in a networking environment, the computing device 10 is connected to the remote system 38 over a network interface 28. The connection between the remote computer 38 and the network interface 28 depicted in FIG. 1 may include a local area network (LAN), a wide area network (WAN), a telephone connection, or the like. These types of networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet.

It will be appreciated that program modules implementing various embodiments of the present invention may be stored in the storage device 32, the non-volatile memory 14, the volatile memory 16, or in a networked environment, in a remote memory storage device of the remote system 38. The program modules may include an operating system, application programs, other program modules, and program data. The processing unit 12 may access various portions of the program modules in response to the various instructions contained therein, as well as under the direction of events occurring or being received over the input interface 24 and the network interface 28.

FIG. 2 illustrates an exemplary environment in which the protocol of the present invention operates. As shown, the environment comprises a plurality of devices 200-205, represented by circles. As used herein, "devices" include server devices 200-202, client devices 203, and client/server devices 204-205. The server devices 200-202 are capable of providing one or more services or carrying out one or more functions. The client devices 203 are capable of instructing the server devices 202 to carry out a designated function or service via a communications link represented by a broken line in FIG. 2. A service could be an external operation, such as adjusting the temperature of a thermostat or switching the lights in a room on or off, or it might involve additional communication between the server device and the client device, such as sending a telephone number from a PDA to a laptop computer. However, a client device is only capable of communicating a service request to a server device if the client device and the server device are capable of communicating using a common protocol. Unfortunately, in today's environment, common protocols are usually shared only by devices produced by the same manufacturer, or by using such devices as modems or special drivers.

As illustrated in FIG. 2, a particular device 200-205 may be both a server device and a client device such as client/server devices 204-205. The client/server devices 204-205 may be capable of instructing other server devices to carry out a designated function while, at the same time, may carry out a function itself. For example, in its client role, a laptop computer might need to retrieve data from a PDA carried by a user, and then in its server role, the laptop might be called on by the user to provide a telephone number directly to a cellular telephone. Thus, the laptop functions as both a client device and a server device. However, in the following description, each device will be discussed only in its role as either a client device or a server device.

FIG. 3 is an exemplary sequential diagram showing the basic steps of the protocol of the present invention. It is important to note that this diagram is meant to depict only the basic functionality of the protocol, and that actual use of the protocol will commonly involve a greater or lesser number of steps. Further, it is important to note that the steps shown and described do not all have to take place in the sequence shown. The sequence represents only a typical use of the available protocol functions which may or may not be followed in actual use.

As shown in FIG. 3, use of the protocol of the present invention does not begin until communication between a client device and a server device is already established at Step 300 using a link protocol, also referred to as a link layer. The protocol of the present invention does not require the use of a specific link layer, but in an exemplary embodiment, the protocol may impose certain requirements such as: 1) allowing for serial ASCII data transfer; and 2) if binary data is to be sent, using standard UUEncode/UUDecode routines to provide the proper conversions to and from ASCII data. Existing link layers which meet these requirements include, but are not limited to, serial cable, IrDA, Bluetooth and TCP/IP sockets.

If a device provides a service, it must be running a protocol server. Once a connection 300 using the link layer is complete, the server will identify itself as being capable of communicating using the protocol of the present invention by issuing a tag line message 301. The issuance of the tag line message 301 signals the actual start of the operation of the protocol of the present invention. In an exemplary embodiment, the tag line message 301 and all subsequent messages are sent using standard 8-bit ASCII characters. In the illustrated embodiment, the tag line message 301 is in the following format:

PROTOCOLNAME VER:N.N [COMMENTS].

where PROTOCOLNAME is the name of the protocol, N.N is the current version of that protocol, and COMMENTS is an optional field which can be used to describe the manufacturer, the date of manufacture, or the like. As previously mentioned, Convergence Corporation has developed a universal protocol, called Service Discovery Transport Protocol ("SDTP") which embodies many of the aspects of this invention. Thus, in the example shown in FIG. 3, the SDTP-enabled server transmits the following tag line message:

SDTP VER:1.0 Convergence Corporation 1998.

Further description of the protocol of the present invention will focus on this specific, exemplary embodiment, but it should be understood that the present invention is not limited to the specifics of the SDTP protocol.

Once the server device issues the tag line message 301, the client device may request the server device to identify the device types it supports and the services the server device provides. This request is performed by transmitting a type-command 302 to the server device. The type-command could be implemented in a variety of forms, but in the illustrated embodiment, the type-command 302 comprises the word "TYPE." Although it is common for the client device to send the type-command 302, it should be understood that sending the type-command is not a required step. For example, a client device may already be aware that a particular service is available from the server device. Advantageously, this may save time in the communication process.

If the server device receives the type-command 302, the server device transmits to the client device a data packet 303-306 describing the devices and services provided by the server device. The data packet 303-306 contains several data fields. Among the data fields are one or more device/service identifiers 303-305, each of which represents either a specific device type or a specific service type. For example a device type may include a thermostat, a door, a pager, a PDA or the like. A service type may include the ability to raise the temperature of a thermostat or to transmit the messages stored in a pager. Although the device/service identifier may be implemented in a variety of forms, in the illustrated embodiment, the device/service identifier subsists in the following form:

x.sub.1 x.sub.2 x.sub.3 -NAME

where NAME is a short (7 characters or less) description of the device or the service, and x.sub.1 x.sub.2 x.sub.3 is a unique three character "identifier." Each of the three characters of the three character identifier is chosen from an alphabet consisting of the characters:

[0 . . . 9], [a . . . z], and [A . . . Z].

In addition, the x.sub.1, x.sub.2 and X.sub.3 characters are chosen such that

(x.sub.1.multidot.x.sub.2)+x.sub.3

forms a unique value. This technique allows for 12161 unique device/services to be used under SDTP while at the same time only requiring 16-bit math to be used when describing a device or a service.

A SDTP server must be able to provide the functionality of at least one device to be classified as a SDTP server. Thus, the data packet 303-306 sent by the server device must include at least one device identifier 303. In the example shown in FIG. 3, the device identifier is X.sub.1A X.sub.2A X.sub.3A -THRMST. In addition, because most server devices support a variety of services, the device identifier 303 is usually followed by multiple service identifiers 304-305. In the example shown in FIG. 3, the service identifiers are X.sub.1B X.sub.2B X.sub.3B -TMPHIGH 304 and X.sub.1C X.sub.2C X.sub.3C -TMPLOW 305. In addition, multiple device identifiers (not shown) may be sent if the server supports multiple device types. For example, a cellular telephone that may also function as a pager would send a device identifier for both the cellular telephone and the pager.

In an exemplary embodiment, each individual device/service identifier 303-305 is sent as a single line of data and is limited to a maximum of 64 characters in length. Advantageously, this technique allows devices having a limited amount of RAM to receive and process a full line of data without facing an overflow condition. The end of a line of data is signaled by transmitting the ASCII <newline> character. Upon transmission of the final data packet 303-306 by the server device, the end of the response is signaled by transmitting an end of response message 306. In an exemplary embodiment, an end of response message 306 includes the ASCII characters "." and "<newline>". Thus, the basic structure of a server device data packet sent in response to a type-command would be as follows:

        ID:DEVICEID[COMMON NAME][COMMENTS]<newline>
        SD:[SERVICEID1][SD_COMMENTS1]<newline>
        SD:[SERVICEID2][SD_COMMENTS2]<newline>
        .vertline.
        .vertline.
        .vertline.
        .<newline>

    TABLE 1
    Device      Device ID     Service            Service ID
    One-way     x.sub.1 x.sub.2 x.sub.3 - Status of the pager x.sub.1 x.sub.2
     x.sub.3 -STAT
    pager       1 WAYPGR
                              Last page received x.sub.1 x.sub.2 x.sub.3
     -PAGERX
                              Displays a page from a x.sub.1 x.sub.2 x.sub.3
     -PAGE
                              LIST command
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REGSTR
                              List pages         x.sub.1 x.sub.2 x.sub.3 -LIST
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Two-way     x.sub.1 x.sub.2 x.sub.3 - Status of the pager x.sub.1 x.sub.2
     x.sub.3 -STAT
    pager       2WAYPGR
                              Last page received x.sub.1 x.sub.2 x.sub.3
     -PAGERX
                              Displays a page from a x.sub.1 x.sub.2 x.sub.3
     -PAGE
                              LIST command
                              Transmits a page   x.sub.1 x.sub.2 x.sub.3
     -PAGETX
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REGSTR
                              List pages         x.sub.1 x.sub.2 x.sub.3 -LIST
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Voice pager x.sub.1 x.sub.2 x.sub.3 - Status of the pager x.sub.1 x.sub.2
     x.sub.3 -STAT
                VOCPGER
                              Last page received is x.sub.1 x.sub.2 x.sub.3
     -PAGERX
                              played
                              Play a page from a x.sub.1 x.sub.2 x.sub.3 -
                              LIST command       PLYPAGE
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REGSTR
                              List pages         x.sub.1 x.sub.2 x.sub.3 -LIST
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Cellular    x.sub.1 x.sub.2 x.sub.3 - Status of the phone x.sub.1 x.sub.2
     x.sub.3 -STAT
    phone       CELLULR
                              Dials a phone number x.sub.1 x.sub.2 x.sub.3
     -DIAL
                              (or instructs to dial)
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REGSTR
                              List numbers in the x.sub.1 x.sub.2 x.sub.3 -
                              phone's number list LISTNUM
                              Add a phone number x.sub.1 x.sub.2 x.sub.3
     -ADDLIST
                              to the list
                              Clears a list entry x.sub.1 x.sub.2 x.sub.3
     -CLRLIST
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Personal    x.sub.1 x.sub.2 x.sub.3 -PDA PDA status         x.sub.1 x.sub.2
     x.sub.3 -STAT
    Data
    Assistant                 Specifies a new    x.sub.1 x.sub.2 x.sub.3
     -CALEVT
                              calendar event
                              Lists upcoming     x.sub.1 x.sub.2 x.sub.3
     -LISTCAL
                              calendar events
                              Lists contacts     x.sub.1 x.sub.2 x.sub.3
     -LISTCON
                              Adds a new contact x.sub.1 x.sub.2 x.sub.3
     -NEWCON
                              Search for a contact x.sub.1 x.sub.2 x.sub.3
     -SEARCH
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Personal    x.sub.1 x.sub.2 x.sub.3 -PC PC status          x.sub.1 x.sub.2
     x.sub.3 -STAT
    Computer
                              Specifies a new    x.sub.1 x.sub.2 x.sub.3
     -CALEVT
                              calendar event
                              Lists upcoming     x.sub.1 x.sub.2 x.sub.3
     -LISTCAL
                              calendar events
                              Lists contacts     x.sub.1 x.sub.2 x.sub.3
     -LISTCON
                              Adds a new contact x.sub.1 x.sub.2 x.sub.3
     -NEWCON
                              Search for a contact x.sub.1 x.sub.2 x.sub.3
     -SEARCH
                              Transmits a file   x.sub.1 x.sub.2 x.sub.3
     -FILETX
                              Receives a file    x.sub.1 x.sub.2 x.sub.3
     -FILERX
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Wired       x.sub.1 x.sub.2 x.sub.3 - Phone status       x.sub.1 x.sub.2
     x.sub.3 -STAT
    Telephone   TELEPH
                              Dials a phone number x.sub.1 x.sub.2 x.sub.3
     -DIAL
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REGSTR
                              Lists the phones   x.sub.1 x.sub.2 x.sub.3 -
                              number list        LISTNUM
                              Adds to the phones x.sub.1 x.sub.2 x.sub.3
     -ADDLIST
                              number list
                              Clears an entry in the x.sub.1 x.sub.2 x.sub.3
     -CLRLIST
                              phones list
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    CID box     x.sub.1 x.sub.2 x.sub.3 -CID Caller ID status   x.sub.1 x.sub.2
     x.sub.3 -STAT
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REGSTR
                              List all caller ID's x.sub.1 x.sub.2 x.sub.3 -
                                                 LISTNUM
                              Last call received x.sub.1 x.sub.2 x.sub.3
     -LATEST
                              Attempt to identify a x.sub.1 x.sub.2 x.sub.3
     -CALLID
                              phone number
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Printer     x.sub.1 x.sub.2 x.sub.3 -PRINT Printer status     x.sub.1
     x.sub.2 x.sub.3 -STAT
                              Print a file       x.sub.1 x.sub.2 x.sub.3 -PRINT
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Fax machine x.sub.1 x.sub.2 x.sub.3 -FAX Fax status         x.sub.1 x.sub.2
     x.sub.3 -STAT
                              Dials a phone number x.sub.1 x.sub.2 x.sub.3
     -DIAL
                              Send a fax         x.sub.1 x.sub.2 x.sub.3 -FAX
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REGSTR
                              List fax numbers   x.sub.1 x.sub.2 x.sub.3 -
                                                 LISTNUM
                              Add to the fax     x.sub.1 x.sub.2 x.sub.3
     -ADDLIST
                              numbers list
                              Clear an entry to the x.sub.1 x.sub.2 x.sub.3
     -CLRLIST
                              list
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Clock       x.sub.1 x.sub.2 x.sub.3 -CLOCK Clock status       x.sub.1
     x.sub.2 x.sub.3 -STAT
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
                              Last alarm         x.sub.1 x.sub.2 x.sub.3 -ALARM
                              Set an alarm       x.sub.1 x.sub.2 x.sub.3 -
                                                 ALARMSET
                              Clear an alarm     x.sub.1 x.sub.2 x.sub.3 -
                                                 ALARMDEL
                              Lists alarm        x.sub.1 x.sub.2 x.sub.3 -LIST
    Stereo      x.sub.1 x.sub.2 x.sub.3 - Stereo status      x.sub.1 x.sub.2
     x.sub.3 -STAT
    Equipment   STEREO
                              Current tuned      x.sub.1 x.sub.2 x.sub.3 -FREQ
                              frequency
                              Set the frequency  x.sub.1 x.sub.2 x.sub.3
     -FREQSET
                              Tune up            x.sub.1 x.sub.2 x.sub.3
     -FREQUP
                              Tune down          x.sub.1 x.sub.2 x.sub.3 -
                                                 FREQDWN
                              Volume up          x.sub.1 x.sub.2 x.sub.3 -VOLUP
                              Volume down        x.sub.1 x.sub.2 x.sub.3 -VOLDN
                              Volume set         x.sub.1 x.sub.2 x.sub.3
     -VOLSET
                              On                 x.sub.1 x.sub.2 x.sub.3 -ON
                              Off                x.sub.1 x.sub.2 x.sub.3 -OFF
                              Play media         x.sub.1 x.sub.2 x.sub.3 -PLAY
                              Change track up    x.sub.1 x.sub.2 x.sub.3 -TRKUP
                              Change track down  x.sub.1 x.sub.2 x.sub.3
     -TRKDWN
                              Set the track      x.sub.1 x.sub.2 x.sub.3
     -TRKSET
                              Fast forward       x.sub.1 x.sub.2 x.sub.3 -FF
                              Rewind             x.sub.1 x.sub.2 x.sub.3 -REW
                              Mute               x.sub.1 x.sub.2 x.sub.3 -MUTE
                              Stop               x.sub.1 x.sub.2 x.sub.3 -STOP
                              Pause              x.sub.1 x.sub.2 x.sub.3 -PAUSE
                              Record             x.sub.1 x.sub.2 x.sub.3
     -RECORD
                              Lists media        x.sub.1 x.sub.2 x.sub.3 -LIST
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Video       x.sub.1 x.sub.2 x.sub.3 -VIDEO Status             x.sub.1
     x.sub.2 x.sub.3 -STAT
    Equipment
                              Channel up         x.sub.1 x.sub.2 x.sub.3 -CHUP
                              Channel down       x.sub.1 x.sub.2 x.sub.3 -CHDWN
                              Current channel    x.sub.1 x.sub.2 x.sub.3 -CHNL
                              Set channel        x.sub.1 x.sub.2 x.sub.3 -
                                                 CHNLSET
                              Volume up          x.sub.1 x.sub.2 x.sub.3 -VOLUP
                              Volume down        x.sub.1 x.sub.2 x.sub.3 -VOLDN
                              Set volume         x.sub.1 x.sub.2 x.sub.3
     -VOLSET
                              On                 x.sub.1 x.sub.2 x.sub.3 -ON
                              Off                x.sub.1 x.sub.2 x.sub.3 -OFF
                              Switch video media x.sub.1 x.sub.2 x.sub.3
     -SWITCH
                              Play media         x.sub.1 x.sub.2 x.sub.3 -PLAY
                              Track up           x.sub.1 x.sub.2 x.sub.3 -TRKUP
    Video                     Track down         x.sub.1 x.sub.2 x.sub.3
     -TRKDWN
    Equipment
    (cont.)
                              Set track          x.sub.1 x.sub.2 x.sub.3
     -TRKSET
                              Fast forward       x.sub.1 x.sub.2 x.sub.3 -FF
                              Rewind             x.sub.1 x.sub.2 x.sub.3 -REW
                              Mute               x.sub.1 x.sub.2 x.sub.3 -MUTE
                              Stop               x.sub.1 x.sub.2 x.sub.3 -STOP
                              Pause              x.sub.1 x.sub.2 x.sub.3 -PAUSE
                              Record             x.sub.1 x.sub.2 x.sub.3
     -RECORD
                              Lists media        x.sub.1 x.sub.2 x.sub.3 -LIST
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Thermostat/ x.sub.1 x.sub.2 x.sub.3 - Thermostat status  x.sub.1 x.sub.2



     x.sub.3 -STAT
    Thermo-     THERMO
    meter                     Set the high       x.sub.1 x.sub.2 x.sub.3 -
                              temperature        TMPHIGH
                              Set the low        x.sub.1 x.sub.2 x.sub.3
     -TMPLOW
                              temperature
                              Force AC to be     x.sub.1 x.sub.2 x.sub.3 -ONAC
                              turned on
                              Force heat to be   x.sub.1 x.sub.2 x.sub.3
     -ONHEAT
                              turned on
                              Force AC to be turned x.sub.1 x.sub.2 x.sub.3
     -OFFAC
                              off
                              Force heat to be turned x.sub.1 x.sub.2 x.sub.3 -
                              off                OFFHEAT
                              Force fan to be turned x.sub.1 x.sub.2 x.sub.3
     -ONFAN
                              on
                              Force fan to be turned x.sub.1 x.sub.2 x.sub.3
     -OFFFAX
                              off
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Generic     x.sub.1 x.sub.2 x.sub.3 - Status of the      x.sub.1 x.sub.2
     x.sub.3 -STAT
    Information GENERIC       information device
    Device
                              List information   x.sub.1 x.sub.2 x.sub.3 -LIST
                              identifiers
                              Display info from id x.sub.1 x.sub.2 x.sub.3
     -DISPL
                              List sub-information x.sub.1 x.sub.2 x.sub.3
     -LISTID
                              List possible query x.sub.1 x.sub.2 x.sub.3
     -LISTQ
                              Make query         x.sub.1 x.sub.2 x.sub.3 -QUERY
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Email device x.sub.1 x.sub.2 x.sub.3 -EMAIL Status of email    x.sub.1
     x.sub.2 x.sub.3 -STAT
                              device
                              Send email         x.sub.1 x.sub.2 x.sub.3 -SEND
                              List emails        x.sub.1 x.sub.2 x.sub.3 -LIST
                              Display emails     x.sub.1 x.sub.2 x.sub.3 -EMAIL
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET
    Security    x.sub.1 x.sub.2 x.sub.3 - Security system status x.sub.1
     x.sub.2 x.sub.3 -STAT
    System      SECURTY
                              Turn security system x.sub.1 x.sub.2 x.sub.3 -ON
                              on
                              Turn security system x.sub.1 x.sub.2 x.sub.3 -OFF
                              off
                              Register           x.sub.1 x.sub.2 x.sub.3
     -REFSTR
                              Return the current x.sub.1 x.sub.2 x.sub.3 -TIME
                              time/date
                              Set the time       x.sub.1 x.sub.2 x.sub.3
     -TIMESET

    TABLE 2
    PARAMTYPE         DESCRIPTION
    S                 String generic string input
    C<CHOICE1.vertline. Choice - Where the client selects from a set of
    CHOICE2.vertline.. . .> Choices described by
     <CHOICE1.vertline.CHOICE2.vertline.etc>
    T                 Time
    B<FLAG1.vertline.FLAG2> Boolean - Client can select from either FLAG1
     or
                      FLAG2
    I                 ID - Used in SDTP list ID's when a service lists
                      ID's that are unique for this session only to
                      identify an item from a LIST.

• Inventors
  Kronz, Jason A.;
• Assignee
  Amazon.com, Inc. (Seattle, WA)
• Published
  Jan-6-2004
• Current US Classes:
  709/200
  709/203
  709/219
  709/226
  709/227
  709/237
  719/319
  719/320
• Application #
  369118
• International Classes
  G06F 015/16
• Field of Search
  709/200-203 709/217-219 709/226-230 709/237 709/313 709/319-320 709/330
• Examiner
  Barot; Bharat
• Agent
  Perkins Coie LLP
• US Patent References:
  5546583
  5732219
  5758083
  5898835
  6038595
  6154738
  6154768
  6157618
  6202094
  6338089
  6347339
  6359892
  6412007
  6430409
  6466971