3Com 1.024.1644-00 manual See the instructions for S13

			Technical Reference
Register	Default	Function
S32	2	Bit-mapped register setup. To set the register,
		see the instructions for S13.
		Bit	Value	Result
		0	1	V.8 Call Indicate enabled.
		1	2	Enables V.8 mode.
		2	4	Reserved.
		3	8	Disable V.34 modulation.
		4	16	Disable V.34+ modulation.
		5	32	Disable 56K modulation.
		6	64	Disable V.90 modulation.
		7	128	Reserved.
S33	0	Bit-mapped register setup. To set the register, see the
		instructions for S13.
		Bit	Value	Result
		0	1	Disable 2400 symbol rate.
		1	2	Disable 2743 symbol rate.
		2	4	Disable 2800 symbol rate.
		3	8	Disable 3000 symbol rate.
		4	16	Disable 3200 symbol rate.
		5	32	Disable 3429 symbol rate.
		6	64	Reserved
		7	128	Disable shaping.
S34	0	Bit-mapped register setup. To set registers, see
		instructions for S13.
		Bit	Value	Result
		0	1	Disable 8S-2D trellis encoding.
		1	2	Disable 16S-4D trellis encoding.
		2	4	Disable 32S-2D trellis encoding.
		3	8	Disable 64S-4D trellis encoding.
		4	16	Disable non-linear coding.

70 56K Voice Faxmodem Internal - User’s Guide