A
AT C
OMMAND
S
ET
O
VERVIEW
Most communications software supports an AT command
line initialization string. The initialization string sets up the
3Com Impact digital modem to negotiate and connect
with a remote modem. Before dialing, the software sends
the initialization string to the 3Com Impact digital modem.
The communications software or server stores the
initialization string and uses it each time it dials. In most
situations, an initialization string is not necessary with the
3Com Impact digital modem. If an initialization string is
required by the communications software or server, use the
Hayes default initialization string.
Software that communicates using AT commands
(ATtention codes) is required to control the 3Com Impact
digital modem. You can enter these codes manually.
However, they are often entered automatically by modem
communications software. For a summary of the AT
command set, see Appendix B, “AT Commands, Registers, and
Result Codes.” Below is a sample AT command line:
AT V1 D 1 800 555 3333 [Enter]
AT
gets the attention of your 3Com Impact digital modem.
V1
sets the digital modem to verbose mode so that it sends
its responses in English words instead of numbers.
D
tells the digital modem to dial an ISDN digital connection
to the phone number that follows.
[Enter]
sends the command line to your 3Com Impact digital
modem.
