Black Box 32144, Manual

Page: 80 / 195

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MODEM 32144
• ESCAPE SEQUENCE (+++).
The escape sequence causes
the modem to escape from the
data transfer mode so it can
interpret commands.
(Alternate characters for the
escape sequence can be
assigned via S register S2.)
• ATTENTION CODE. AT, the
attention code, must begin all
command lines. There are a
few exceptions—but only a few.
• COMMAND SEQUENCE. For
dialing, a command line begins
with AT and is followed by D
and the phone number. Other
commands should be placed
before the dial command—or
after the dial command if it is
terminated with a semicolon—
for example:
AT M2 V1 D 555-1212; S2=1O
This instructs the modem to:
Keep speaker on (M2), send word
result codes (V1), dial (D) 555-
1212, end dial command (;), set
register 2 to 1 (S2=1), and go on-
line and wait for carrier (O).
Characters not in the command
set are ignored during the dial
command. For this reason,
punctuation or spaces can be
included in the telephone number
to make it easier to read:
AT DT 9,(212)555-1234 or AT DT
9, 212 555 1234
• A/ COMMAND. Repeats the
commands included in the
previous command line.
Because the AT is also
repeated, no AT is needed to
begin this command, nor is a
carriage return needed. A/ is
useful for redialing a telephone
number.
• BACKSPACE KEY. The
backspace key deletes the last
character entered (provided
there is no intervening carriage
return) and can be used for
simple editing.
• CARRIAGE RETURN [CR]. A
carriage return is required at
the end of a command line.
The modem will not execute a
command without it. A carriage
return is sent from the DTE
keyboards; a period, which may
be entered via the modem’s
front panel (PHONE LCD
screen), has the same function.
(On most keyboards, the
carriage return [CR] key is
labeled “Enter” or “Return.”)
• DIAL COMMAND
MODIFIERS. Several modifiers
can be used with the basic D
(dial) command to alter dialing
operations. These modifiers are
listed and explained briefly
below—they are explained in
detail in
Section 5.4