Multi-Tech Systems MT2834BA, MT2834BL manual 25bis Responses Result Codes, 25bis AT Commands

Appendix D - V.25bis Operation

V.25bis Responses (Result Codes)

When in V.25bis mode (the AT$V1 command executed), your modem provides you with several responses which can help you follow the progress of V.25bis operations. These are similar to the Result Codes associated with AT Command mode operation. The V.25bis responses are in the form of three- character mnemonics as listed below:

INC	Incoming Call (same as RING indicator)
VAL	A valid V.25bis command has been attempted
DLCt	Call delayed for t minutes (number on Delayed list)
CFlrr	Call failure indicator where rr equals:
	et - Engaged tone (same as BUSY)
	nt - Call Answered but No Answer Tone
	ab - Call Not Answered
	fc - Number on Forbidden List
	ns - Number not stored in memory
	ua - User Abort
	nd - No Dialtone
	ff - Forbidden List full
LSNmm;dd...dd	Phone number in V.25bis memory
LSDmm;dd...dd	Phone number on the Delay list
LSFmm;dd...dd	Phone number on the forbidden list
CON ssss	Connection at ssss speed (if X1 in effect)

V.25bis AT Commands

The AT commands associated with V.25bis mode are described as follows. Note that one command enables and disables V.25bis mode and the rest are only operable in the V.25bis mode.

Enable/Disable V.25bis Mode ($V) Command

The function of the $V command is to select the V.25bis mode in asynchronous mode. (Synchronous mode is set up with switches. For example, the modem could be in AT command mode, (AT$V1), and if synchronous mode is enabled with AT Command mode enabled, then V.25bis mode is selected). Prior to executing this command, make sure that your modem is properly set up to perform the type of operation you will be performing. Refer to the initialization section of this appendix for information about modem set-up. When in V.25bis mode, most normal AT commands will also function (except D,N,O and U).

V.25bis operates in asynchronous or synchronous modes (depending on the position of DIP-Switch #12), and does not check for terminal speed (so do not change speeds while in this mode) or parity. In synchronous mode, speed is not important since the internal clocks provide synchronization.

To place your modem in V.25bis mode from asynchronous mode, enter the AT$V1 command. To return to AT command mode, enter the AT$V0 command. AT$V2 allows you to run one V.25bis command from AT command mode without leaving AT command mode (the V.25bis command follows $V2 on the command line).

Change Serial Baud Rate (CSP) Command

The CSP command will change the serial baud rate of your modem by entering CSPsssss where sssss

can equal:
0300	=	300 bps
1200	=	1200 bps
2400	=	2400 bps
4800	=	4800 bps
9600	=	9600 bps
19200	=	19200 bps
38400	=	38400 bps
57600	=	57600 bps
115200 =		115200 bps

Multi-Tech Systems, Inc. MT2834BA/BL Series User Guide 109