AC International MTA128ST-USB manual Ring, S51

Chapter 4 - AT Commands, S-Registers, and Result Codes

not define a means of conveying Calling Party information to the terminal for ISDN voice calls. CLI information is included only with the first RING message for a given incoming call and appears as:

RING

FM: 5552000 TO: 5551000

If the Calling Party Number information is not included in the incoming SETUP message, the RING message appears as follows:

RING

TO: 5551000

	If the Called Party Number information is not included in the incoming SETUP message,
	the RING message appears as follows:
	RING
	FM: 5552000
	If neither the Called Party Number nor Calling Party Number is included in the incoming
	SETUP message, the RING message contains no additional information.
S-Register:	S51
Function:	POTS Port Dial Tone Suppression
Unit:	Decimal ASCII code
Range:	n = 0, 1
Default:	0

Description: S51 only affects NET3 switch type and voice/modem/fax calls attempted on the POTS port. Some NET3 switches have a hot dial tone (dial tone that sounds very loud). If the dial tone is too loud, the TA cannot recognize any or most of the DTMF digits. This is a similar to trying to communicate with another person in a very loud train station— your voice is drowned out by the noise of other people and the trains. By setting S51=1, the TA keeps the receive gain of the POTS port low until a DTMF digit is received. After a DTMF digit is received, the gain is set back to whatever !RXG was set to before the phone, modem, or fax went off-hook (!RXG6 by default). !RXG does not need to be adjusted.

S-Register: S52

Function: Auto-Protocol Detection

Unit:	Decimal ASCII code
Range:	0, 1, or 2
Default:	1 (Detect)

Description: 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.

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