Multi-Tech Systems BA-Series User Manual
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Chapter 4 - Command Mode
Off Hook H
You can make the modem hang up (go On Hook). Entering
ATH1
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
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
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
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
%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.