3 AT Commands
CommPlete Communications Server 27
&P1 sets a pulse dial ratio of 67 ms break to 33 ms make.
&RDnSquare Wave Ring Detect
n
= 0 or 1
Default: &RD0 (U.K. and International models)
&RD1 (North American models)
The ring back sound that you hear when you dial a number is generated at the local telephone office or
PBX. Normally, it is a sine wave analog tone. However, some PBXs generate square wave rings that can go
undetected by normal ring detection circuits, resulting in a failure to make a connection. To enable your
modem to detect square wave rings, use the &RD1 command.
&RD0 enables sine wave ring detection only.
&RD1 enables sine wave and square wave ring detection.
$TnCalling Tone
n
= 0 or 1
Default: $T1
The $T command enables or disables the modem’s calling tone, which is required by some European
countries to identify the caller as a modem.
$T0 enables the calling tone.
$T1 disables the calling tone.
#TnTrellis-Coded Modulation
n
= 0 or 1
Default: #T1
The #T command enables or disables trellis-coded modulation (TCM) on the modem. There is usually no
need to disable TCM, except for an unusual line condition called impulse noise.
#T0 disables TCM.
#T1 enables TCM.