Black Box 32144, Manual

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26
MODEM 32144
indicate that the modem is tran-
smitting and receiving data). (The
speed may be other than 9600 bps;
the modem will automatically
adjust to the speed of the remote
modem, provided the remote unit
is a compatible modem.)
To terminate a call, first enter
the escape se++. When the
OK response appears on the DTE
screen, enter the command AT H.
An alternate method is to drop the
DTR signal from the DTE. If you
are using a computer with a
communication software program,
follow the program’s instructions
for initiating and terminating calls.
2.4.2 2-W
IRE
D
IAL
V.25
BIS
M
ODE
(Q
UICK
S
ETUP
2–4)
The modem supports three types of
V.25 bis operation—asynchronous;
synchronous, character-oriented; or
synchronous, bit oriented. There is
a Quick Setup for each V.25 bis
type, as shown in
Table 2-1 . For
V.25 bis operation, the modem
must be configured to use the
same data protocol (asynchronous;
synchronous, character-oriented;
or synchronous, bit-oriented) as
the attached DTE. If you have
selected the correct V.25 bis Quick
Setup, the data protocol will be set
automatically to the correct setting.
V.25 bis mode operation and
commands are explained in
detail in
Chapter 6 .
Asynchronous V.25 bis Operation
In asynchronous applications,
V.25bis commands (listed in
Chapter 6 ) may be entered from
the DTE keyboard. As an example,
the simplest command sequence is
CRN 3331234 . In response to this
command, the modem sends a VAL
result code (indicating that the
command has been accepted),
dials the telephone number, 333-
1234, and then waits for an answer
tone from a remote modem. If no
carrier is detected within a given
time (45 seconds by default), the
modem automatically releases the
line and sends a CFI NT result code.
Spaces entered in the command
line for readability are ignored;
therefore,
CRN 555 1212 will have
the same effect as
CRN5551212
.
The data format of the DTE
should be set to 7 data bits with
even parity and one stop bit. (Note
that the default DTE interface rate
is 38,400 bps in asynchronous
mode.)
When a phone number is
successfully dialed, the EIA status
screen on the modem will typically
look like this:
D TR MR RS CS
9600 CD