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Microsoft Windows Logo Program System and Device Requirements  —  131

the termination is on in North America, but off in all other countries, where phone companies unconditionally provide the termination.

Note: The Network Device Class Power Management Reference Specification, Version 1.0 or later, does not yet define wake-up mechanisms for ISDN adapters or any network communications adapter that uses ATM signaling.

B7.4.4.2 Device meets Windows Logo network adapter requirements
B7.4.4.3 Device supports synchronous high-level data link control framing

High-level Data Link Control (HDLC) framing is a standard for sending synchronous data. Other framing methods are allowed if the miniport driver provides simple HDLC-framed, synchronous PPP packets to NDIS.

B7.4.4.4 NDIS interface and driver support raw, unframed synchronous B channel I/O

The internal ISDN device and the driver must support raw, unframed (non-HDLC) synchronous B channel I/O at 64 Kbps per B channel, with each B channel individually accessible. This support enables H.320 as well as voice calls over ISDN without audio breakup.

For these raw interfaces, the direct path to each B channel must support synchronous transmission and reception of H.221 frames, which are of 20 ms duration. Since underruns or overruns cause degraded audio, hardware buffering must be adequate to prevent B channel underruns and overruns.

This can be achieved by making buffering software configurable with adequate range to handle foreseeable real-world conditions. The miniport driver should make I/O completion callbacks to NDIS for each I/O buffer as soon as the I/O for that buffer is complete and should not coalesce or delay callbacks.

B7.4.4.5 ISDN Driver supports unattended installation, with limitations

Configuration of the dependent parameters, such as SPIDs and switch-type IDs, must be done through the ISDN configuration wizard included in the operating system.

B7.4.4.6 Device includes software-selectable terminating resistors

If the ISDN device has an S/T-interface for connecting additional ISDN devices and has configurable terminating resistors, they must be software configurable. The software selectable resistors can be selected on or off. The default value of termination is on in North America, but off in all countries where phone companies unconditionally provide the termination.

B7.4.4.7 ISDN modem supports asynchronous-to-synchronous conversion and RFC 1662

Because ISDN is a synchronous service and an ISDN modem connects t a logic asynchronous USB port on the PC, the device must provide some means of converting asynchronous data to synchronous data. The asynchronous-to-synchronous conversion must support the requirements identified in RFC 1662.

These types of ISDN devices are treated as modems, not as internal ISDN devices supported using NDIS WAN miniports. In the external case, the primary impli­cation is that the operating system will send byte-level PPP, also known as asynchronous PPP. In the NDIS WAN case, the implication is that the operating system will send bit-level PPP, also known as synchronous PPP.

Because ISDN is a synchronous service and an ISDN modem connects to an asynchronous port on the system, the device must provide some means of converting asynchronous data to synchronous data.

B7.4.4.8 ISDN modem supports required command set

© 1999-2002 Microsoft Corporation. All rights reserved.

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