Multi-Tech Systems ISIHP-4SD, ISIHP-4U Default 1 Detect, S54 Force 56 Kbps B-Channel Data Rate

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

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