3Com 1.024.1644-00 manual Default Function, Bit Value Result

			Technical Reference
Register	Default	Function
S10	14	Sets the duration, in tenths of a second, that the modem
		waits to hang up after loss of carrier. This guard time
		allows the modem to distinguish between a line
		disturbance from a true disconnect (hang up) by the
		remote modem.
		Note: If you set S10 = 255, the modem will not hang up
		when carrier is lost. Dropping DTR hangs up the modem.
S11	70	Sets the duration and spacing, in milliseconds, for tone
		dialing.
S12	50	Sets the duration, in fiftieths of a second, of the guard time
		for the escape code sequence (+++).
S13	0	Bit-mapped register. Select the bit(s) you want on and set
		S13 to the total of the values in the Value column. For
		example, ATS13 = 17 enables bit 0 (value is 1) and bit 4
		(value is 16).
		Bit	Value	Result
		0	1	Reset when DTR drops.
		1	2	Reset non-MNP transmit buffer from
				1.5K to 128 bytes.*
		2	4	Set backspace key to delete.
		3	8	On DTR signal, auto dial the number
				stored in NVRAM at position 0.
		4	16	At power on/reset, auto dial the
				number stored in NVRAM at position
				0.
		5	32	Reserved
		6	64	Disable quick retrains.
		7	128	Disconnect on escape code.

66 56K Voice Faxmodem Internal - User’s Guide