Off Hook H, Force Answer Mode a | Multi-Tech Systems BA-Series

Chapter 4 - Command Mode

Off Hook H

You can make the modem hang up (go On Hook). Entering ATH1<RETURN> brings the line Off Hook, just as if you picked up the telephone set. You can hang up by entering ATH0 or ATH (the default is 0 when no number is entered).

Escape Sequences- Entering Command Mode While Still On-Line +++AT<CR>

It is possible to cause the modem to enter Command mode after the modem has gone on-line with a remote modem, without disconnecting the call. This is done by entering an Escape Code. The default Escape Code used by the modem is three plus signs (+++) followed by the letters A and T, up to sixty command characters (most typically “H”, to hang up), and a RETURN. The number of command characters allowed after +++ AT<CR> , is defined by S-Register S34. S-Register S34 defaults to ten command characters.

When this is done, the modem escapes to Command Mode, executes the command (if any), and then remain in Command mode. For example, to hang up the modem at the end of a call, enter

+++ATH and hit RETURN. There is no need to incorporate pauses before and after the plus signs, as done in earlier modems.

BREAK AT<CR>

The modem provides an alternative Escape method, using a Break signal as the Escape Code. The Break signal allows the start-stop DTE (data terminal equipment) to signal the modem without loss of character transparency. With this method, a BREAK signal is used instead of the three plus signs. The BREAK is followed by the letters A and T, up to 60 command characters, and RETURN. When this is done, the modem executes that command, but remains in On-Line mode unless the command was to hang up and/or reset the modem (an H or Z), in which case the modem would be in the Command Mode after executing that command.

Escape Sequence Options - Entering Command Mode While On-Line %E

As mentioned, the default escape sequence setting is for the modem to respond to the +++ escape method. Optional settings are for the modem to respond to the Break method, for the modem to respond to either the +++ or the Break Methods, for the modem to ignore both methods and not escape, for the modem to respond with no "OK" to +++, and for the modem to respond with "OK" to

+++. The %E command is used to select these options, as follows:

%E0	=	Modem Won’t Escape
%E1	=	+++ AT<CR> Method (default)
%E2	=	Break Method
%E3	=	Either +++ or Break Methods
%E4*	=	No "OK" Response to +++
%E5*	=	"OK" Response to +++

*The %E4 and %E5 commands enable or disable an "OK" response, which is required by some software packages during an escape sequence.

Force Answer Mode A

You can force the modem into Answer mode with the modem’s A command.

Entering ATA when in Command mode immediately brings your modem off-hook, out of Command mode and into On-Line Answer mode, and causes it to transmit its carrier signal over the phone line. If no responding carrier tone is received by your modem within forty-five seconds (or some other time as determined by S-Register S7), your modem stops transmitting its tone, hangs up, and goes back into Command mode.