ADTRAN ISU 2X64 user manual Type, = Fallback, = Ppp, Dial Mode

			Appendix D: S-Register List
S54.......PROTOCOL		Rate adaptation protocol type.
	TYPE	1	= Clear Channel (no rate adaptation) (default)
		2	= BONDING mode 1
		3	= SAP (Simple Asynchronous Protocol)
		4	= T-link
		5	= V.110
		6	= V.120
		9	= DSU 57.6 kpbs asynchronous
		11	= FALLBACK
		12	= PPP
S55	DIAL MODE	Selects dialing interface.
		0	= Front panel only (dialing from front panel is al-
		ways available) (default)
		1	= RS-366 dialing port
		2	= AT commands
		3	= V.25 bis dialing
S56.......ECHO TONE		Enables an echo tone which suppresses the echo can-
		cellers in a voice circuit. Can be used to trick the
		switch to allow sending data over a line optioned for
		voice ISDN service.
		0	= None (default)
		1	= Answer
		2	= Originate
		3	= Both
S57.......DDS TEST		Allows an ISU 2x64 optioned as a leased line unit to
		respond to either DDS inband latching loopback and/
		or V.54 loopback commands.
		0	= No Rem Lpbks
		1	= DDS Accepted
		2	= V.54 Accepted (default)
		3	= DDS + V.54 Accepted

S58.......CALL SCREENING Allows the ISU 2x64 to screen incoming calls.

0= Answer any call (default)

1= Answer only calls from numbers matching those stored in SN0 through SN9.

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