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Chapter 13: Dialing, Answering, & Clearing Calls Using AT Commands
When using your ISDN TA/V, there are five ways that a call can be dialed, the
first two of which you will already have used when working through Part I of
this manual:
• A digital voice call can be manually dialed using a telephone attached to
the ISDN TA/V.
• A data call can be dialed by selecting the appropriate option using
communications-software program or
Intro
in the DTE interface attached
computer, and typing the number to be called.
• A data call can be dialed from the DTE interface attached computer’s
keyboard, or the
CONTROL
port attached terminal, using the AT
command language.
• A data call can be dialed from the DTE interface attached computer’s
keyboard using V.25bis dialing commands. See
Chapter 18
for further
details about this option.
• A preset data call can be automatically dialed by the ISDN TA/V when the
control signal DTR (Data Terminal Ready) is detected on the ISDN
TA/V’s DTE interface.
13.1 Using the D Command
The D command, followed by the number that you wish to dial, forms the AT
command line that is used to instruct your ISDN TA/V to dial a number.
Following the command language rules as specified earlier, issuing the
command
ATD12345678<CR>
would instruct the ISDN TA/V to dial the
number: 12345678.
The current status of your ISDN TA/V is displayed on its front-panel LCD.
During a dialing sequence the display will read
Dialing xxxxxx
, followed by
Remote Ring
or
Call Failed
depending on the state of the line.
When it is making a call, your ISDN TA/V behaves in much the same way as a
human telephone user in that it connects to the line, dials the required
number, and then listens for a response. If the ISDN TA/V hears an engaged
tone, or doesn’t get an answer within a configurable time period, it hangs up.
13. Dialing, Answering, and Clearing
Calls Using AT Commands
