Chapter 7: AT Commands and Registers

NOTE

You may not want to use certain other protocols, such as HP Block Mode, with MNP. Such protocols have particular timing requirements that can interfere with MNP’s effectiveness.

Auto-reliable mode (\N3) allows the modem to communicate with remote systems which support the MNP or LAPM reliable link and with systems that do not support the reliable link. In auto-reliable mode, the answering modem looks for incoming MNP or LAPM protocol characters from the remote modem. If it detects them within approximately three seconds, it tries to establish a reliable link connection.

When the modem is set to auto-answer in auto-reliable mode, you can shorten this 3-second period by using the %A command with \C2.

NOTE

If both modems are set to auto-reliable mode, a normal connection or no connection could result due to noise on the telephone line.

LAPM reliable mode (\N4) uses the LAPM reliable link to provide error detection and automatic retransmission of data if an error occurs. This ensures that communications between your system and the remote system are error-free. The remote system must also be equipped to handle an LAPM reliable link. The modem attempts to establish an LAPM reliable link immediately after making a connection. If the attempt fails, the modem disconnects.

LAPM reliable mode with fallback to normal mode (\N5) attempts to establish an LAPM reliable connection. If the LAPM connection attempt fails, the modem falls back to a normal connection.

LAPM reliable mode with fallback to MNP reliable mode (\N6) attempts to establish an LAPM reliable connection. If the LAPM connection attempt fails, the modem then tries to establish an MNP reliable connection.

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CSMIM-T1 Hardware Installation Guide

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Cabletron Systems manual CSMIM-T1 Hardware Installation Guide