AT Command Set and S-Registers
4-4
Issue 2 May 1995
Table 4-1. AT Command Reference (3 of 18)
AT
Command Description
E
n
COMMAND CHARACTER ECHO
This command controls whether or not the characters you
enter from your computer’s keyboard are echoed back to
your monitor when the modem is in Command mode.
E0
Disables echo.
E1
Enables echo.
H
n
HOOK
This command lets the modem go on-hook to disconnect a
call or off-hook to make the telephone line busy.
H0
The modem goes on-hook (disconnects a call).
H1
The modem goes off-hook.
I
n
MODEM IDENTIFICATION
This command displays information about your modem.
I
0
Displays product code “240”.
I
1
Displays firmware revision number (first three digits
only, see
I
19 for full display).
I
2
Performs a checksum, which verifies the integrity of
the firmware running in your modem.
I
19
Displays the version number of the firmware running
in the modem.
M
n
SPEAKER ON/OFF CONTROL
M0
Speaker always off.
M1
Speaker on until carrier signal becomes active.
M2
Speaker always on.
M3
Speaker off during dialing and on until carrier signal
becomes active.
O
RETURN TO ONLINE DATA MODE
This command allows you to exit Online Command mode
and return to Data mode.
P
PULSE DIAL (Used with rotary telephone lines)
This command configures the modem for Pulse dialing. To
disable Pulse dialing issue the T (tone dial) command. Tone
dialing is the default factory setting.
