Black Box MD1641A, MD1640A manual Series II Intelligent DATA/FAX Modems

SERIES II INTELLIGENT DATA/FAX MODEMS

Entering AT automatically sets the modem’s speed to match the speed of the computer or terminal, and also sets the modem’s parity.

The AT characters alert the modem that a command follows. The AT Command can also be used to clear the command buffer, by simply typing AT and hitting RETURN.

The letter D in a command causes the modem to dial the numbers immediately following it (e.g., ATD7247465500). You have a choice of either pulse (ATDP) or tone (ATDT) dialing methods.

The Modem responds with “CONNECT” on your video display after the number is dialed and a connection signal is detected (since the Modem defaults to Enhanced V.34/V.42/V.42bis, the actual response is "CONNECT LAPM COMPRESSED”), if the Series II Modem “connects” with a similar modem (see section 5.3 Result Code Summary). The modem is now in “On-Line”mode, and is ready to communicate with a host site.

If no connection signal is detected within 45 seconds (this time period can be adjusted by S-Register S7), the Modem goes On Hook/hangs up and returns to Command mode. At this point, your video displays “NO CARRIER”.

Enter +++ATH to Hang Up On-Line (bring modem on-hook), and terminate the modem's On-Line mode. At this point, your video displays “OK”.

In addition to the call originating capabilities, the Modem can also automatically answer incoming calls. You need not be present. You can, however, control the situation by configuring the modem to either answer or not to answer, or to answer after a specified number of rings. This is done by setting the value of S-Register S0 (modem defaults to automatically answer an incoming call after one ring). Refer to Chapter 6 for S-Register details.

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