AT&T DataPort PCX Modem User Manual page 44

AT Commands and S-Registers
Table B-1. AT Command and S-Register List (5 of 21)
AT Command/
S-Register
H n
I n
L n
Description
HOOK CONTROL
Controls the modem's on-hook or off-hook status.
The ATH or ATH0 command causes the modem to go
on-hook, disconnecting the call. It also forces the
modem into Talk mode; if the telephone receiver is
lifted off-hook before the ATH0 command is entered,
the connection is maintained.
The ATH1 command causes the modem to go
off-hook, causing a "Make Busy" condition. It also
forces the modem into data (Originate) mode. This is
like the ATD command with no number, except that
automatic disconnects do not occur.
H, H0 On-hook
H1 Off-hook
IDENTIFICATION
Returns information about the modem.
Displays product code (14400).
I, I0
I1 Displays a checksum value.
Displays OK result code.
I2
Displays the firmware revision level, model,
I3
and interface.
Displays a firmware-dependent code.
I4
Displays country code.
I5
I6 Displays data pump model and revision
code.
SPEAKER VOLUME
Adjusts the volume of the modem's speaker.
L, L0, L1 Low volume (Default for &F0)
L2 Medium volume (Default for &F1)
L3 High volume
Issue 2 July 1995
B-5