USB Modem协议

Universal Serial Bus CDC Subclass Specification for Wireless Mobile Communications
Devices
Revision 1.1
February 9, 2007
Wireless Mobile Communication Devices Revision 1.1 Revision History Rev Date
Filename Comments 1.1 2/9/07
WMC110.doc Final edits as per February 2007 CDC meeting Specify a reserved value in Table 5-3. Remove “For Review and Discussion Only” footer 1.0 11/23/2001 CDC_WMC10.doc
Remove “For Review and Discussion Only” footer; replace “TBD”
placeholders with numeric values.
Please send comments via electronic mail to cdc@
USB Wireless Mobile Communication Devices
© Copyright 2006, USB Implementers Forum, Inc.
All rights reserved.
ii February 9, 2007
Revision 1.1 Wireless Mobile Communication Devices
Copyright © 2007, USB Implementers Forum, Inc.
All rights reserved.
A LICENSE IS HEREBY GRANTED TO REPRODUCE THIS SPECIFICATION FOR INTERNAL USE ONLY. NO OTHER LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, IS GRANTED OR INTENDED HEREBY.
USB-IF AND THE AUTHORS OF THIS SPECIFICATION EXPRESSLY DISCLAIM ALL LIABILITY FOR INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, RELATING TO IMPLEMENTATION OF INFORMATION IN THIS SPECIFICATION. USB-IF AND THE AUTHORS OF THIS SPECIFICATION ALSO DO NOT WARRANT OR REPRESENT THAT SUCH IMPLEMENTATION(S) WILL NOT INFRINGE THE INTELLECTUAL PROPERTY RIGHTS OF OTHERS.
THIS SPECIFICATION IS PROVIDED "AS IS” AND WITH NO WARRANTIES, EXPRESS OR IMPLIED, STATUTORY OR OTHERWISE. ALL WARRANTIES ARE EXPRESSLY DISCLAIMED. NO WARRANTY OF MERCHANTABILITY, NO WARRANTY OF NON-INFRINGEMENT, NO WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, AND NO WARRANTY ARISING OUT OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE.
IN NO EVENT WILL USB-IF OR USB-IF MEMBERS BE LIABLE TO ANOTHER FOR THE COST OF PROCURING SUBSTITUTE GOODS OR SERVICES, LOST PROFITS, LOSS OF USE, LOSS OF DATA OR ANY INCIDENTAL, CONSEQUENTIAL, INDIRECT, OR SPECIAL DAMAGES, WHETHER UNDER CONTRACT, TORT, WARRANTY, OR OTHERWISE, ARISING IN ANY WAY OUT OF THE USE OF THIS SPECIFICATION, WHETHER OR NOT SUCH PARTY HAD ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.
All product names are trademarks, registered trademarks, or service marks of their respective owners. February 9, 2007 iii
Wireless Mobile Communication Devices Revision 1.1
Contributors to Version 1.0
Mobile Computing Promotion Consortium (MCPC)
Nakatani Fujitsu
Limited
Tatsuya
Kenji Oguma NEC Corporation
Shinji Kamiya DENSO Corporation
Keiichi Murakami Fujitsu Limited
Paul E. Berg MCCI
Moore MCCI
Terry
Minoru Ohwada MITSUBISHI ELECTRIC CORPORATION
Noriko Fukumasu NEC Corporation
Noriko Norimatsu NEC Corporation
Hisayuki Yamanaka NOKIA Japan Co. Ltd
Chang-Jiang Zhang NOKIA Japan Co. Ltd
Seiji Abe NTT DoCoMo, Inc.
Hideo Uchizono NTT DoCoMo, Inc.
Toshiharu Uchida Pioneer Corporation
Hajime Shimizu SHARP BUSINESS COMPUTER SOFTWARE INC.
BUSINESS COMPUTER SOFTWARE INC.
Yasue SHARP
Kazuhito
Tanaka SUNCORPORATION
Yoshizane
Takafumi Ito Toshiba Corporation
Hiroshi Kinugasa Toshiba Corporation
USB Device Working Group Communications Device Committee
Jim Wilcox Apple Computer Inc.
Russ Winsper Apple Computer Inc.
Neira Ericsson
Elena
Morten Christiansen Ericsson Semafor
Silverman KLSI
Joel
Overtoom Motorola
Eric
Okazaki NEC
Corporation
Ryota
Katsuhiko Kobayashi NEC Engineering, Ltd.
Richard Petrie Nokia Mobile Phones
James Scales Nokia Mobile Phones
Julie
Bendig Qualcomm
Guo Qualcomm
Hongshi
Contributors to Version 1.1
USB Device Working Group Communications Device Committee
2007
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Revision 1.1 Wireless Mobile Communication Devices
Russ Winsper Apple Computer Inc.
Balden Belcarra
Bruce
Guo Broadcom
Jun
Morten Christiansen Ericsson AB
Berkama HP
Alan
Joel
Silverman K-Micro
Meads MCCI
Brian
Decuir MCCI
Joe
FitzRandolph MCCI
Peter
Moore MCCI
Terry
Taylor Motorola
Ken
Richard Petrie (editor) Nokia
Rand Nokia
Janne
Soukko Nokia
Tero
Self Symbian
Dale
Turner Symbian
John
Mohammad Synopsys
Saleem
February 9, 2007 v
Wireless Mobile Communication Devices Revision 1.1
Table of Contents
1Introduction (1)
1.1Purpose (1)
1.2Scope (1)
1.3Related Documents (2)
1.4Terms and Abbreviations (3)
2Management Overview (5)
3Assumptions and Constraints (7)
3.1Compliance (7)
4Functional Overview (10)
4.1Device Organization (10)
4.2Device Operation (11)
4.2.1Contention (11)
4.3Function Models (12)
4.4Interface Definitions (13)
4.5Endpoint Requirements (13)
4.6Device Models (13)
5Class Specific Codes (14)
5.1Communications Class Subclass Codes (14)
5.2Communications Class Protocol Codes (14)
5.3Communications Class Functional Descriptor Sub-Type Codes (14)
5.4Communications Class Management Element Request Codes (15)
5.5Communications Class Notification Element Request Codes (15)
6Functional Characteristics (16)
6.1WHCM Logical Handset (16)
6.1.1Functional Topology (16)
6.1.2WHCM Descriptors (16)
6.1.2.1WHCM Interface Descriptor (16)
6.1.2.2Communications Class Header Functional Descriptor (16)
6.1.2.3WHCM Functional Descriptor (17)
6.1.2.4Communications Class Union Functional Descriptor (following WHCM interface) 17
6.1.3Management Elements (19)
6.1.4Notifications (20)
6.2Data/Fax Modem Functions (21)
6.2.1Functional Topology (21)
6.2.2Descriptors (21)
6.2.2.1ACM Interface Descriptor (21)
6.2.2.2Communications Class Header Functional Descriptor (22)
6.2.2.3Abstract Control Management Functional Descriptor (22)
6.2.2.4Call Management Functional Descriptor (23)
6.2.2.5Communications Class Union Functional Descriptor (23)
6.2.2.6Notification Endpoint Descriptor (24)
6.2.2.7Data Class Interface Descriptor (24)
6.2.2.8Data Class Header Functional Descriptor (24)
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6.2.2.9Endpoint Descriptors (25)
6.2.3ACM Management Elements for Data/Fax (25)
6.2.4ACM Notifications for Data/Fax (25)
6.2.5Contention (26)
6.3Voice Functions (27)
6.3.1Functional Topology (27)
6.3.2Descriptors (27)
6.3.2.1TCM Interface Descriptor (27)
6.3.2.2Communications Class Header Functional Descriptor (28)
6.3.2.3Telephone Control Model Functional Descriptor (28)
6.3.2.4Communications Class Union Functional Descriptor (28)
6.3.2.5Notification Endpoint Descriptor (29)
6.3.3Management Elements (29)
6.3.3.1SendEncapsulatedCommand (29)
6.3.3.2GetEncapsulatedResponse (29)
6.3.4Notifications (30)
6.3.5Contention (30)
6.4LAN Frame Functions (31)
6.4.1Functional Topology (31)
6.4.2Descriptors (31)
6.4.2.1Ethernet Networking Control Model Interface Descriptor (31)
6.4.2.2Communications Class Header Functional Descriptor (31)
6.4.2.3Ethernet Networking Functional Descriptor (32)
6.4.2.4Communications Class Union Functional Descriptor (32)
6.4.2.5Notification Endpoint Descriptor (33)
6.4.2.6Data Class Interface Descriptor, Alternate Setting Zero (33)
6.4.2.7Data Class Header Functional Descriptor (33)
6.4.2.8Data Class Interface Descriptor, Alternate Setting not Zero (34)
6.4.2.9Data Class Header Functional Descriptor (34)
6.4.2.10Endpoint Descriptors, Alternate Setting not Zero (34)
6.4.2.11Additional Alternate Data Class Settings (34)
6.4.3Management Elements (35)
6.4.4Notifications (35)
6.4.5Contention (35)
6.5OBEX Functions (36)
6.5.1Functional Topology (36)
6.5.2OBEX Descriptors (36)
6.5.2.1OBEX Interface Descriptor (36)
6.5.2.2Communications Class Header Functional Descriptor (37)
6.5.2.3OBEX Functional Descriptor (37)
6.5.2.4Union Functional Descriptor (37)
6.5.2.5OBEX Service Identification Functional Descriptor (Optional) (38)
6.5.2.6OBEX Communications Interface Endpoint Descriptors (40)
6.5.2.7Data Class Interface Descriptor, Alternate Setting Zero (40)
6.5.2.8Data Class Header Functional Descriptor (41)
6.5.2.9Data Class Interface Descriptor, Alternate Setting not Zero (41)
6.5.2.10Data Class Header Functional Descriptor (42)
6.5.2.11Endpoint Descriptors, Alternate Setting not Zero (42)
6.5.3Management Elements (42)
6.5.3.1Establishing OBEX transport connection (42)
6.5.3.2Suspend, Resume and Remote Wakeup (42)
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6.5.3.3Session Request Protocol (43)
6.5.4Notifications (43)
6.5.5Contention (43)
6.6Device Management Functions (44)
6.6.1Functional Topology (44)
6.6.2Device Management Descriptors (44)
6.6.2.1Device Management Interface Descriptor (44)
6.6.2.2Communications Class Header Functional Descriptor (44)
6.6.2.3Device Management Functional Descriptor (45)
6.6.2.4Device Management Notification Endpoint (45)
6.6.3Management Elements (45)
6.6.4Notifications (46)
6.6.5Contention (46)
6.7MDLM Transport Functions (47)
6.7.1Functional Topology (47)
6.7.2Descriptors (47)
6.7.2.1MDLM Interface Descriptor (47)
6.7.2.2Communications Class Header Functional Descriptor (48)
6.7.2.3Mobile Direct Line Model Functional Descriptor (48)
6.7.2.4MDLM Detail Functional Descriptor (48)
6.7.2.5Communications Class Union Functional Descriptor (49)
6.7.2.6Notification Endpoint Descriptor (50)
6.7.3Management Elements (50)
6.7.4Notifications (50)
6.7.5Contention (51)
7Device Requests (52)
7.1Encapsulating AT Command Data (52)
8Device Descriptors (54)
8.1Standard USB Interface Descriptors (54)
8.1.1Device Descriptor (54)
8.1.2Configuration Bundle (54)
8.1.2.1Additional Function-Specific Descriptors (54)
8.1.2.2Command Set Functional Descriptor (54)
8.1.2.3Command Set Detail Functional Descriptor (55)
Appendix A:Windows Driver Architecture (56)
Appendix B:OBEX Connections (58)
List of Tables
Table 2-1: Sample Function Representation (5)
Table 5-1: Communications Class Subclass Code (14)
Table 5-2: Communications Class Protocol Codes (14)
Table 5-3: Communications Class Functional Descriptor Sub-Type Codes (14)
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Table 5-4: Communications Class Management Element Request Codes (15)
Table 5-5: Communications Class Notification Element Request Codes (15)
Table 6-1: Communications Class Header Functional Descriptor (16)
Table 6-2: Wireless Handset Control Model Functional Descriptor (17)
Table 6-3: Union Functional Descriptor (17)
Table 6-4: Communications Class Abstract Control Model Interface Descriptor (21)
Table 6-5: Communications Class Header Functional Descriptor (22)
Table 6-6: Abstract Control Management Functional Descriptor (22)
Table 6-7: Call Management Functional Descriptor for Data/FAX Facilities (23)
Table 6-8: Union Functional Descriptor for Data/Fax Facilities (23)
Table 6-9: Data Class Interface Descriptor for Data/FAX Facilities (24)
Table 6-10: Data Class Header Functional Descriptor (25)
Table 6-11: ACM Management Elements for Data/Fax Functions (25)
Table 6-12: ACM Notification Elements for Data/Fax Functions (26)
Table 6-13: Communications Class Telephone Control Model Interface Descriptor (27)
Table 6-14: Communications Class Header Functional Descriptor (28)
Table 6-15: Telephone Control Model Functional Descriptor (28)
Table 6-16: Union Functional Descriptor for Voice Call Facilities (29)
Table 6-17: Communications Class Ethernet Networking Control Model Interface Descriptor . 31 Table 6-18: Ethernet Networking Functional Descriptor (32)
Table 6-19: Union Functional Descriptor for LAN frame facilities (32)
Table 6-20: Data Class Interface Descriptor for LAN frame facilities, Setting 0 (33)
Table 6-21: Data Class Interface Descriptor for LAN frame facilities, non-zero Setting (34)
Table 6-22: Communications Class OBEX Model Interface Descriptor (36)
Table 6-23: Communications Class Header Functional Descriptor (37)
Table 6-24: OBEX Control Model Functional Descriptor (37)
Table 6-25: Union Functional Descriptor for OBEX Facilities (37)
Table 6-26: Functional Descriptor for OBEX service identification (38)
Table 6-27: Bitmask values for bmObexRole (39)
Table 6-28: UUID values defined by WMC OBEX (39)
Table 6-29: Data Class Interface Descriptor for OBEX facilities, Setting 0 (41)
Table 6-30: Data Class Interface Descriptor for OBEX facilities, non-zero Setting (41)
Table 6-31: Communications Class Device Management Interface Descriptor (44)
Table 6-32: Communications Class Header Functional Descriptor (45)
Table 6-33: Device Management Functional Descriptor (45)
Table 6-34: Communications Class Mobile Direct Line Model Interface Descriptor (47)
Table 6-35: Communications Class Header Functional Descriptor (48)
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x February 9, 2007 Table 6-36: Mobile Direct Line Model Functional Descriptor (48)
Table 6-37: MDLM Detail Functional Descriptor (49)
Table 6-38: Union Functional Descriptor for MDLM Facilities (49)
Table 6-39: MDLM-Specific-Write (50)
Table 6-40: MDLM-Specific-Read (50)
Table 6-41: MDLM-Specific-Read (51)
Table 8-1: Command Set Functional Descriptor (55)
Table 8-2: Command Set Detail Functional Descriptor (55)
List of Figures
Figure 3-1: Reference Model (7)
Figure 4-1. Device Structure (10)
Figure 6-1: WHCM Union Functional Descriptor and Device Structure (19)
Figure A-1 Windows Driver Architecture (57)
Figure B-2 OBEX transport control and indication primitives (59)
1 Introduction
1.1 Purpose
The USB interface uses a common and simple cable connector, which supports the connection of various types of equipment. When used with wireless communications devices, USB is a vital interface that handles various media over one type of cable using a unified protocol.
Mobile (cellular phone) wireless service technology is normally characterized by generation: •First generation (or 1G) services are analog, and provides no special data services.
•Second generation (or 2G) services use TDMA or CDMA, and are loosely characterized as “digital” services. Only limited data service is available on these services. The leading 2G service in Europe is GSM; TDMA and CDMA are common in other geographical locations •Updated second generation (or 2.5G) services build on the digital services by adding protocols that are more suitable for data. They provide bandwidth of up to about 144 Kbps. The best
known 2.5G service is GPRS, based on GSM. 2.5G services typically provide no additional
multimedia services, and are based on the existing spectrum and towers.
•Third generation (or 3G) services are a major upgrade to the services offered by 2G equipment. With the advent of third generation services, various kinds of computing equipment can be connected to wireless communications devices via USB. (This computing equipment is generically referred to as “Mobile Terminal Equipment”). The capabilities of third-generation mobile equipment are much greater than those of second-generation equipment. Multiple calls can be handled on a single communications terminal. “Multimedia communication” (including Internet sessions, voice calls, and special purpose data services such as fax and modem emulation) will take place at the high speeds provided by the third generation wireless networks. To support these services, this document indicates one way of providing USB connectivity for terminal equipment containing multiple functions, for example audio, data communications, and status monitoring functions.
1.2 Scope
This document specifies new device subclasses intended for use with Wireless Mobile Communications devices, based on [USBCDC1.2], [USBPSTN1.2] and [USBECM1.2].
Because this specification is based on several CDC based specifications, the question arises of how to resolve conflicts. The intention of this specification is that all material presented here be upwards-compatible extensions of these other specifications. In cases, where information is repeated from other documents, the originating document shall be treated as the controlling document. New numeric codes for subclass codes, protocol codes, management elements, and notification elements are defined in [USBCDC1.2] and are repeated in this document for clarity.
1.3 Related Documents
Reference Description
[3GPP27.007] AT command set for User Equipment (UE), 3rd Generation Partnership Project; Technical Specification Group Terminals, Document 27.007,Version 3.9.0 (June 2001). Available on-line at
/ftp/Specs/2001-06/R1999/27_series/27007-390.zip.
The reserved numbers section of official Bluetooth website .
[Bluetooth Reserved
Numbers]
[C-S0017-0] 3GPP2 TSG.C Specification C-S0017-0. Specifies AT command sets to be used for cmda2000 mobile terminals. Available on-line from /public_html/specs/tsgc.cfm .
[GSM07.07] ETSI GTS GSM 07.07 V5.0.0 (1996-07) Digital cellular telecommunications system (Phase 2+); AT
command set for GSM Mobile Equipment (ME) (GSM 07.07), ETSI. Available on-line at /. [INTTD] USB Telephony Devices: Interfaces for Value-Add Feature Set, Version 1.00, June 19,2000, Intel
Corporation.
[LEACH1998] UUIDs and GUIDs, Paul J. Leach et al, IETF draft draft-leach-uuids-guids-01.txt., February 4, 1998. [MICBUS] Guidelines for Bus and Device Specifications , Version 1.0a, March 29, 2000, Microsoft Corporation. This specification is available online from Microsoft, /whdc/archive/specguide.mspx [MICMFD] Designing Multifunction Devices for Windows Operating Systems, Version 1.0, April 25, 2000, Microsoft Corporation. This specification is available online from Microsoft,
/whdc/device/mf/mfdesin.mspx.
[OBEX1.2] IrDA Object Exchange Protocol IrOBEX, V1.3. This specification is available online from the website .
[OPENC309] DCE: Remote Procedure Call, Open Group CAE Specification C309 ISBN 1-85912-041-5 28cm. 674p. pbk.
1,655g. 8/94
[PCCA101] PCCA STD-101, Data Transmission Systems and Equipment - Serial Asynchronous Automatic Dialing and Control for Character Mode DCE on Wireless Data Services, Portable Computer and Communications
Association. Available on-line at /standards.1 Annexes to this document are:
[PCCA101-A] common commands, in main document (== TIA/EIA-678 Annex A)
[PCCA101-D] Pad Control, /standards/Annex_d.doc, (== TIA/EIA-678 Annex D)
[PCCA101-F] Commands for wireless networks, /standards/Annex_f.doc (== TIA/EIA-678 Annex B) [PCCA101-I] Commands for Analog Cell Phones, /standards/Annex_i.doc (== TIA/EIA-678 Annex C) [PCCA101-L] Commands for CDPD modems, /standards/Annexl20.PDF (not in TIA/EIA-678)
[PCCA101-O] Commands for Wakeup control, /standards/Annex_o_ballot_version.doc (not in TIA/EIA-678)
[USB2.0] Universal Serial Bus Specification, revision 2.0 (also referred to as the USB Specification). This specification is available on the World Wide Web site .
[USBAUD1.0] Universal Serial Bus Device Class Definition for Audio Devices, Release 1.0. This specification is available on the World Wide Web site .
[USBCDC1.2] Universal Serial Bus Class Definitions for Communications Devices, Version 1.2. This specification is available on the World Wide Web site .
[USBDFU1.0] Universal Serial Bus Device Class Specification for Device Firmware Upgrade, Release 1.0. This
specification is available on the World Wide Web site .
[USBHID1.1] Universal Serial Bus Device Class Definition for Human Interface Devices, Version 1.1. This specification is available on the World Wide Web site .
[USBECM1.2] Universal Serial Bus USB CDC Subclass Specification for Ethernet Control Model Devices, Release 1.2.
This specification is available on the World Wide Web site .
[USBMASS1.1] Universal Serial Bus Mass Storage Class Specification Overview, Release 1.1. This specification is available on the World Wide Web site .
1 PCCA STD-101 was adopted as TIA/EIA-678. The content is identical but has been rearranged.
[USBPSTN1.2] Universal Serial Bus USB CDC Subclass Specification for PSTN Devices, Release 1.2. This specification is available on the World Wide Web site .
1.4 Terms and Abbreviations
Term Description
2G Second generation wireless telecommunication systems
2.5G Second generation wireless telecommunication systems, with enhanced data services.
3G Third generation wireless telecommunication systems
3GPP Third Generation Partnership Project: trade organization planning the migration from GSM to 3G service. (See /)
3GPP2 Third Generation Partnership Project Two: trade organization planning the migration from CDMA to 3G service. (See /).
ACM Abstract Control Model, a way of representing data/fax modem capabilities in USB devices, defined by [USBCDC1.2].
ARIB Association of Radio Industries and Businesses
BARB Bluetooth Architecture Review Board
CDMA Code Division Multiple Access (see /).
cdmaOne cdmaOne describes a complete wireless system that incorporates the CDMA/IS-95 air interface.
cdma2000 cdma2000 is Telecommunications Industry Association (TIA) standard for third-generation technology that is an evolutionary outgrowth of cdmaOne. See 3GPP2.
control plane Communications Class interface used to perform device management and optionally call management. See [USBCDC1.2].
DFU Device Firmware Upgrade, a standard means of updating firmware over USB. See [USBDFU1.0].
EDGE Enhanced Data rates for GSM and TDMA/136 Evolution – an enhanced version of GPRS compatible with GSM and TDMA/136
GOEP Generic Object Exchange Profile
GPRS General Packet Radio Services, a 2.5G data service for GSM networks
GSM Global System for Mobile telecommunications, a complete 2G wireless system. See /
Term Description
IMT-2000 International Mobile Telecommunication-2000 – the generic standard name for 3G technology. See /imt, and especially
http://www.itu.int/imt/what_is/roadto/index.html, which gives a very good overview
of how cellular technologies align.
IrDA Infrared Data Association. (/)
MCPC Mobile Computing Promotion Consortium, /.
MDLM Mobile Direct Line Model, a way of migrating some of the protocol functions of wireless terminal adapters to the USB host system. A mechanism for implementing MDLM
transport is defined by this document.
Equipment
ME Mobile
Terminal
MT Mobile
Exchange
OBEX Object
PABX Private Automatic Branch eXchange
PDC Personal Digital Cellular
System
PHS Personal
Handy-phone
Adapter
TA Terminal
TDMA Time Division Multiple Access, a 2G modulation system
TDMA/136 A complete wireless service based on the TDMA/IS-136 air interface. See
/.
TE Terminal Equipment, it indicates the communications equipment in the USB host
UUID Universal Unique Identifier
WHCM Wireless Handset Control Model
WMC Wireless Mobile Communications, the abbreviation for this device subclass
2 Management Overview
With 2.5G and 3G cell phone services, manufacturers and network operators need to define a common way for handling multiple data and voice services in a single handset.
This specification represents multi-function communications handset devices as composite devices. Each potential facility is modeled, if possible, using a pre-existing device class. This allows reuse of existing class drivers. Additional Communications Device subclasses are defined for new application areas specific to wireless handsets.
Although some of the capabilities can only be used after a circuit is established, each capability is always explicitly represented in the descriptors. This allows for a simpler usage model for current operating systems.
Because the 3G standards and existing cell phones use AT commands for computer-directed call control, this specification extends the Telephone Control Model by adding a new protocol code that indicates that AT commands are used for call control.
Table 2-1 illustrates the representations. Note that in Table 2-1, the notation “pp” is used to indicate that the protocol code is one of the protocol codes which identifies variants of the AT command set.
Table 2-1: Sample Function Representation
Function Representation
Endpoints
voice (AT-command call control) Telephone Control Model (TCM) with
AT commands (02-03-pp) + Audio Interrupt IN + audio stream ISO OUT + audio stream ISO IN
voice (AT-command call control, plus ability to use handset’s keypad in host, and to use handset’s speaker and microphone as host peripherals) Telephone Control Model (TCM) with
AT commands (02-03-pp) + Audio +
HID
TCM Interrupt IN + audio stream ISO
OUT (to network) + audio stream ISO
IN (from network) + audio stream ISO
OUT (to headset earpiece) + audio
stream ISO IN (from headset
microphone + HID Interrupt IN
fax/modem ACM
(02-02-pp) + Data Interrupt IN + Data Class Bulk OUT &
Bulk IN
OBEX OBEX (02-0Bh0B-00), + Data Class Data Class Bulk OUT & Bulk IN
Ethernet Frame (fixed service) CDC Ethernet Networking Control
Model (ECM) (02-06-00) + Data Interrupt IN + Data Class Bulk OUT & Bulk IN
Device Management Device Management (02-09h09-pp) Interrupt
IN The remainder of this specification is organized into the following outline.
•Assumptions and Constraints
•Functional Overview
•New class code values
•Functional Characteristics for each subclass, including:
1.Functional Topology
2.Descriptors
3.Management Elements
4.Notifications •Device Requests •Device Descriptors
3 Assumptions and Constraints
This standard assumes the reference model shown in Figure 3-1.
Figure 3-1: Reference Model
In this figure, the handset (or Mobile Equipment, “ME”) consists of an MT and one or more TAs. The Mobile Terminal (MT) has only a facility to access the air interface. It can be thought of as the radio transmitter and receiver. Each Terminal Adapter (TA) is provided with one call facility or management capability. If a TA is provided with a call facility, that means it provides the data formatting, media conversions, and protocol capabilities to make that kind of call, to the USB host at Reference B. The presence of a TA reflects an abstract capability of the ME; at any given time, it might not be possible to use the TA to make that kind of call, due to external circumstances.
Within the limits of USB, any number of TAs may be provided. Applications use the kind of TA that provides the device model that meets their requirements. For a Voice Application, the application opens a Telephone Control Model TA and uses USB Audio. For a modem application, the application accesses an Abstract Control Model TA. When multiple applications need to be operated at the same time (i.e., Multi-call), the ME must have sufficiently many TAs to support all the applications or calls concurrently. Of course, the ME and the network interface must also be able to support such concurrency; otherwise, only a subset of the calls can proceed.
The ME can also provide connections to the USB host at Reference A. In this case, some or all of the TA functions can be off-loaded from the ME to the USB host. However, due to the variety of standards and requirements, this specification cannot cover the details of this interface. Instead, this specification provides a standardized way for operators or regional groups to agree on a private interface, while still making it possible for cognizant third-party software to recognize and operate conforming devices.
3.1 Compliance
In addition to meeting all the requirements of the USB core specification [USB2.0], devices conforming to this specification must meet the following requirements. Some of these requirements are testable; others must be enforced by design.。