Multi-Tech Systems MT5600SMI-P32, MT5600SMI-XL34 manual Register Unit Range Default Description S21

Chapter 5 – AT Commands, S-Registers, and Result Codes

Register	Unit	Range	Default	Description
S21			52 (34h) V.24/General Bit-Mapped Options Status: Indicates the status of
				command options.
				Bits 0 - 1	Reserved (0)
				Bit 2	CTS behavior (&Rn)
				0 =	CTS tracks RTS (&R0)
				1 =	CTS always on (&R1) (Default.)
				Bits 3-4	DTR behavior (&Dn)
				0 =	&D0 selected
				1 =	&D1 selected
				2 =	&D2 selected (Default.)
				3 =	&D3 selected
				Bit 5	RLSD (DCD) behavior (&Cn)
				0 =	&C0 selected
				1 =	&C1 selected (Default.)
				Bit 6	DSR behavior (&Sn)
				0 =	&S0 selected (Default.)
				1 =	&S1 selected
				Bit 7	Long space disconnect (Yn)
				0 =	Y0 (Default.)
				1 =	Y1
S22			117 (75h) Speaker/Results Bit-Mapped Options Status: Indicates the status
				of command options.
				Default:	117 (75h) (01110101b)
				Bits 0-1	Speaker volume (Ln)
				0 =	Off (L0)
				1 =	Low (L1) (Default.)
				2 =	Medium (L2)
				3 =	High (L3)
				Bits 2-3	Speaker control (Mn)
				0 =	Disabled (M0)
				1 =	Off on carrier (M1) (Default.)
				2 =	Always on (M2)
				3 =	On during handshake (M3)
				Bits 4-6	Limit result codes (Xn)
				0 =	X0
				4 =	X1
				5 =	X2
				6 =	X3
				7 =	X4 (Default.)
				Bit 7 Reserved
S23			0	General Bit-Mapped Options Status: Indicates the status of
				command options.
				Bits 0-6	Not used
				Bits 6-7	Guard tone (&Gn)
				0 =	None (&G0) (Default.)
				1 =	None (&G1)
				2 =	1800 Hz (&G2)
S24	seconds	0–255	0	Sleep Inactivity Timer: Sets the length of time, in seconds, that the
				modem will operate in normal mode with no detected telephone line
				or DTE line activity before entering low-power sleep mode. The timer
				is reset upon any DTE line or telephone line activity. If the S24 value
				is zero, neither DTE line nor telephone inactivity will cause the
				modem to enter the sleep mode.
S25	0.01 s	0–255	5	Delay to DTR OFF: Sets the length of time that the modem will
				ignore DTR for taking the action specified by &Dn. Its units are
				seconds for synchronous modes and one hundredths of a second for
				other modes.
S26	0.01 s	0–255	1	RTS-to-CTS Delay: Sets the time delay, in hundredths of a second,
				before the modem turns CTS ON after detecting an OFF-to-ON

transition on RTS when &R0 is commanded. Pertains to synchronous operation only.

Multi-Tech Systems, Inc. SocketModem MT5600SMI Developer’s Guide 77