Multi-Tech Systems ISIHP-2U - Manual (Page 131)

MultiModemISI Hybrid Series, ISIHP-2S/2U/4S/4U/4SD 131
Terminal Adapter AT Commands & S-Registers
Range: n=0—Disable,
n=1—Detect,
n=2—Detect and Select
Default: 1 (Detect)
Enables or disables the ability to identify the reception of V.110, V.120,
X.75, or PPP data calls. The TA determines the type of call by checking for
protocol information in the SETUP message or by matching protocol
information received on the B-channel once connected if no protocol
information is available in the SETUP message. Once the protocol is
determined, the TA will switch its data protocol to match. Upon disconnect
the TA will revert its data protocol selection back to the protocol that was
selected before the call was received when S52=1 “Detect”. If S52=2
“Detect and Select”, then the TA will not revert the protocol selection,
rather it will keep the detected data protocol as the new protocol selection.
“Detect and Select” is useful for applications where the TA receives a call
and then the software performs callback. Callback calls should be made
with the same protocol that was used by the client so “Detect and Select”
enables this possibility. However, if an initialization string or &Fn
command is given to the TA that changes the protocol after the
disconnection, then “Detect and Select” will not be effective. Make sure no
commands are given to the TA that will change the data protocol when using
“Detect and Select” if callback is involved to ensure that the callback call
uses the correct data protocol.
S54 Force 56 Kbps B-Channel Data Rate
Unit: Decimal ASCII code
Range: n=56 (Kbps) or 64 (Kbps)
Default: 64 (Kbps)
S54 can be used to force a 56 Kbps B-channel data rate in order to make 56
Kbps data calls.
S55 POTS Port Call Control
Unit: Decimal ASCII code
Range: 1, 2, 17, 18
Default: 1
Allows you to set the type of information transfer capability for calls placed
from the POTS port either by a telephone, modem, or fax. Some Central
Office (CO) switches keep track of the type of line each customer has, and
if that line is labeled as a data line (modem or fax), it will not accept a