All driver-based modems must use a WDM-based driver solution as described in the Modem Devices section of the Windows DDK.
B6.1.2 General Modem - Industry Standards
Note: This list provides complete titles and web locations for references cited. The listing of a reference here does not imply that complete compliance with that reference is a Windows Logo Program requirement.
B126.96.36.199 Bellcore Technical References
B188.8.131.52 Communications Device Class Power Management Reference Specification, V. 2.0
B184.108.40.206.1 Modem supports Communications Device Class Power Management specification
The Communications Device Class Power Management Reference Specification, Version 1.0, provides definitions for the OnNow device power states (D0–D3) for modems. The specification also covers the device functionality expected in each power state and the possible wakeup event definitions for the class.
There are no Wake on Ring requirements.
B220.127.116.11.2 External USB modem complies with all related USB specifications
Universal Serial Bus Specification, Revision 1.1 or later
Universal Serial Bus Class Definitions for Communication Devices, Version 1.0 or later.
Note: A device can be USB 2.0 compliant and still function in full-speed mode (i.e. at 12Mbps), just like it used to as a USB 1.1 full-speed device.
For compatibility with Unimodem and Windows USB serial drivers, a USB modem that incorporates the modem controller function must support the mandatory and optional requests and notifications for Abstract Control Model Serial Emulation defined in section 18.104.22.168.1 of the Universal Serial Bus Class Definitions for Communication Devices, V. 1.0.
Alternatively, external modems may support IEEE 1394 or Bluetooth instead of USB. If implemented as external Bluetooth modems, they must support one of the applicable profile defined by the Bluetooth SIG specifications, such as Dial Up Networking (K:7.). See Specification of the Bluetooth System, Volume 1: Core, v1.0 B, and Volume 2: Profiles, v1.0 B.
B22.214.171.124 Analog modem supports standard capabilities
B126.96.36.199.1 V.250 Extended AT Command Set (formerly V.25 ter).
B188.8.131.52.1.1 If V.92 is implemented, it must be compliant.
B184.108.40.206.1.2 The following AT Commands must be defined in the modem driver INF file. See the Modem section of the Windows DDK for more information on these AT commands.
Blind Dial (see B220.127.116.11.3)
DialOption – WaitForQuiet
DialOption – WaitForDialTone
ErrorControl (see B18.104.22.168.1)
Blacklist and delay response (see B22.214.171.124.3)
Diagnostics – AT#UD (see B126.96.36.199.3.6)
V.250 GCI Country Select (see B188.8.131.52.2)
See B184.108.40.206 for general information on Standard Modem Command Sets and INFs.
If the AT command for a particular function is implemented, the corresponding V.250 AT command must be supported.
Windows Unimodem does not use the following commands directly; therefore, these are not in the sample INF and are not required: ICF, MA, EB, ESR, ETBM. These commands are only required if the function is controllable in the modem by way of AT commands; in that case, the standard V.250 commands defined here must be included
B220.127.116.11.1.3 The modem controller must meet these additional requirements:
Software-upgradeable modem controller (upgradeable ROM or Windows modem) is not required.
If the Unimodem Diagnostics command, AT#UD, is implemented, it must comply with the standard.
B18.104.22.168.2 If V.250 is implemented, modem must be certified by the local telecom regulation body in all countries supported by GCI commands.
GCI commands are part of V.250. Country codes can be found in T.35.
B22.214.171.124.3 If implemented, wireless/cellular modem supports appropriate control commands.
B126.96.36.199.3.1 If Caller ID detection is implemented, modem supports Caller ID Reporting using VCID and VRID commands
If Caller ID detection is implemented, reporting must be controlled with the AT VCID command from V.253. If Caller ID message reporting is implemented, it must be controlled with the AT VRID command from V.253.
Wireless modems and look-alike modems include the common types, such as North American analog cellular, cellular digital packet data (CDPD), GSM, and other digital cellular systems, as well as several other types.
B188.8.131.52.3.3 All wireless and cellular modems must use the WS46 command, which selects the WAN.
The TIA-678 WS46 command has codes to indicate the system in which the modem can operate. For example, the following values, quoted from Table 4 of the standard, are useful.
Public telephone network (that is, a normal wireline modem)
TIA IS-136 TDMA digital cellular (Personal Communications System)
Windows has registry keys that support analog cellular modems. Windows also supports data access in GSM and other wireless modem types.
B184.108.40.206.3.4 If digital cellular control is implemented, Mobile PC modem supports appropriate C digital cellular standards
If digital cellular support is implemented, the following appropriate digital cellular control standards must be supported.
System and services
GSM system: data, fax, voice
North American CDMA: data and fax
North American TDMA: data and fax
Digital cellular communications equipment must default to using error correction on the radio link. For example, for GSM 7.07, the modem must initialize to CBST=,,1 (which selects a “nontransparent” air interface).
To allow data cards to use GSM/ISDN V.110 “fast access” where available in the network, CBST=71,, ( 9600 bits per second (bps) V.110) must be a valid setting.
B220.127.116.11.5 Connection to two distinct V.90 host modems (such as 3Com and Conexant) at 40 Kbps or better.
B18.104.22.168.6 If modem supports call control, media detection uses V.251.
Modems that support call control must support the ITU V.251 standard for PC-controlled call control, including:
DCE-controlled V.8 operation with DTE notification.
DTE-controlled V.8 operation ( values of 2, 3, and 4).
DTE-controlled V.8 bis operation.
Backward compatibility for media detection with terminals using V.25 signaling, for example, data calling tone and fax calling tone.
Backward compatibility for media detection with older modems, for example, V.32 and V.32 bis.
Modems must provide a means for turning on the V.8 Calling Indicator signal for originating calls. Modems must also meet requirements stated in the Videophone-ready Modem Handbook, Version 1.0, which describes the specific implementation details essential to support H.324 voice-band video conferencing.
B22.214.171.124.7 If caller ID is implemented, modem complies with ITU-T V253 section 126.96.36.199
See ITU-T V253 section 188.8.131.52 for details about correctly implementing caller ID reporting.
Note: Software-based modems are not required to capture caller ID while the system is either in ACPI S3 sleep state or resuming from S3 state.
B184.108.40.206.2 Connection to reference modem; see test documentation for list.
B220.127.116.11.3 Error control and blind dial.
B18.104.22.168.4 AT commands:
ATA - accept ringing
ATD - dial
ATE - echo setting
ATH - hangup
ATI - get modem information
S0 - S0 register (0 value is to disable to accept ringing)
ATV - response code style
ATZ - reset
- - Initialize
- - Hard/Soft flow control
B22.214.171.124.1 32 Kbps (PIAFS 1.0) connectivity to PIAFS modem.
B126.96.36.199.2 Connection to DC-6S in PIAFS 1.0 and to SII NS-2482-30 (dial-up).
B188.8.131.52.3 If modem supports delayed/blacklisted numbers, modem generates appropriate error messages for delayed and blacklisted numbers (where applicable).
During certain international Post, Telephone, and Telegraph certification processes, modems must support the delayed and blacklisted numbers feature. For details, see European Telecommunications Standards Institute (ETSI) ETS 300 001.
For Windows compatibility, modems that support delayed and blacklisted number tables must generate end-user legible error messages to report these conditions.
Provide modem INF file drivers that translate these error messages for Unimodem and TAPI.
B184.108.40.206 ISDN modem - See B7.4.
B220.127.116.11 Global System for mobile communications or digital cellular phone support, if implemented, includes required command and protocol support
B18.104.22.168 Analog V.90 modem tested in conjunction with digital V.90 modems commonly deployed by ISPs
This requirement states a basic criterion for modem functionality. While operating in the default modem configuration on TIA-3800 line I01d-loop 3, the modems must be able to transfer a typical file in 40 minutes or less, simultaneously in both directions, without hanging up or otherwise aborting the transfer. Data transmission is required to be run directly on the modems without the use of an additional protocol such as Zmodem.
B22.214.171.124.1 If impairment combination 2C4 is implemented, complies with ITU-T Recommendation V.56 bis.
The analog V.90 modem subject to this requirement must meet it when connected to digital V.90 modems commonly deployed by Internet service providers (ISPs). For modems certified for operation only in countries outside of North America, the requirement is for operation on impairment combination 2C4, as specified in International Telecommunication Union – Telecommunication Standardization Sector (ITU-T) Recommendation V.56 bis. V.56 bis. specifies that the modem must be connected to an identical analog modem, rather than a digital V.90 modem.
Telecommunications Industry Association (TIA) TSB-38 provides detailed test procedures and criteria.
B126.96.36.199.2 Modem must be able to repeatedly connect
This requirement must be met with an overall call completion success ratio of 97 percent with a minimum of 50 iterations, and without the modem stalling in an unresponsive, inoperable state.
B188.8.131.52.3 Modem pair must be able to sustain the connection for at least 30 minutes
At no less than 90 percent of the initial connection rate, with no more than 1 retrain, using the same TSB-3800 line I01d-loop 3 specified for use under B6.1.4.
B184.108.40.206 Telephony applications meet communication and performance requirements
B220.127.116.11.1 System with telephony applications uses a common set of audio I/O devices for system audio and telephony applications
If the system enables telephony applications such as speakerphone, IP telephone, and so on, then for each type of audio I/O device, the same device must be usable for both system audio and telephony. For example, the same set of speakers must be usable for both system audio and speakerphone functions. When using a headset, users must not need to change plug locations when switching from, for example, listening to CD-audio to speaking on the phone.
This requirement ensures that one convenient, unambiguous I/O connector is provided for each type of audio I/O device. It does not mandate that all audio I/O is delivered to a single I/O device at all times. For example, providing system audio sounds to the speakers while simultaneously using a headset for IP telephony would not be prohibited.
B18.104.22.168.2 Telephony applications provided with a system meet industry telephony performance requirements
If the system enables telephony applications that support devices, such as speakerphone or handset telephony, using various types of connections, such as plain old telephone service (for example, through a voice modem) or IP (through a network connection), the applications provided with the system must comply with telecommunications industry requirements for such parameters as send and receive loudness, echo, and so forth.
Speakerphone applications must meet the requirements in ITU-T Recommendation P.340, Transmission characteristics of hands-free telephones. Other applications must meet the requirements in ITU-T Recommendation P.310, Transmission characteristics for telephone band (300-3400 Hz) digital telephones. For additional information for IP telephony functions, see U.S. Committee T1 Technical Report No. 56, Performance guidelines for voiceband services over hybrid internet/PSTN connections, which provides useful guidance for IP telephony functions.
Note: There is no requirement to support any ITU recommendation equivalent to TIA-3800 for the testing of pulse-coded modulation (PCM) modem operation.
B22.214.171.124 Data modem supports digital connection to support host-side V.90 operation
V.90 depends on a digital connection for the host-side modem to the public telephone network, typically using T1 or ISDN. Server modems should be designed for digital connection, to support host side V.90, where digital connections are available.
B6.1.5 General Modem - FAQs
B126.96.36.199 Current Modem FAQs
Modems are not required on any system.
FAQ Date: January 31, 2001
B188.8.131.52 Voice recording and playback capabilities [Logo Program correction]
The FAQ is incorporated at B184.108.40.206.8.
B220.127.116.11 WDM support for driver-based modems [Logo Program clarification]
B18.104.22.168 Total execution time for DPCs queued by a WDM modem [Clarifications]
Note: Total execution time for DPCs is a recommendation. This is not tested.
At any instant in time, the total execution time for all delayed procedure calls (DPCs) that have been queued by a WDM driver-based modem, but have not dequeued and started executing, should not exceed 500 milliseconds.
A WDM driver-based modem should not continuously disable thread preemption for more than 4.4 milliseconds. This guideline accommodates 400 microseconds of interrupts being disabled together with two back-to-back episodes of 2.0 milliseconds of extended processing at DISPATCH_LEVEL, as up to four 500-microsecond DPCs execute sequentially.
FAQ Date: October 7, 1998