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Commetrex’ 60112 Fax Modem Bundle includes Commetrex’ V.21, V.27ter, V.29, and V.17 in a C-coded reference design and versions optimized for the Texas Instruments TMS320C6200 and TMS320C5400 DSPs in a TI XDAIS Algorithm Standard-conformant and Commetrex format. The optimized versions provide up to 16 simultaneous V.17 receivers for each 100-MCPS on a TI ‘C6400 or 7 simultaneous modems on the ‘C5400. .

Commetrex first deployed its modems in 1994. Hundreds of developers in Asia, North America, and Europe have since licensed the technology, and dozens of OEMs have integrated the modems into proprietary embedded environments. Everyday, millions of fax pages are sent and received with Commetrex’ fax modems.

These modems have exceptional performance in high-noise and ISI channels. They can withstand large noise bursts, dropouts, and amplitude changes.

• Thirteen years of field experience

• Highly optimized C/assembly code

• High noise and drop-out immunity

• Texas Instruments XDAIS compliant

• MSP Consortium M.100 compliant

• Fully supported

• 12-month warranty/no-charge updates

• High system densities

• Low integration cost

• Low support costs

• High customer satisfaction

Module	Performance (mega-cycles/sec)	Code Space (bytes)	Constants and tables (bytes)	Per-Instance Memory(bytes)
Total	5.3 (V.17R)	49,656*	14,938*
V.17 transmitter	3.7	5,984	5,036	472
V.17 receiver	5.3	28,000	7,158	2076
V.27ter/V.29 transmitter**	4.6 (V.27: 4.0)	6,904	4,228	504
V.27ter/V.29 receiver**	5.1 (V.27: 5.5)	23,264	3,996	1632
V.21 transmitter	2.1	3,488	2,080	192
V.21 Receiver	3.9	4,160	1,804	200

*Total memory utilization does not equal the sum of individual modems due to common elements
**V.27ter and V.29 are table-driven and share a single code set and static data space.

In general, the results of the bit-error rates of Commetrex’ modems exceed the performance of the equivalent fax modems offered by the market leader of modem “chips”. Tests were performed for three different line-impairment conditions:

1) The ideal channel where the maximum noise for the modem to have a successful three-page transmission was measured. The lower the number the greater the noise, so the better the result.

V.17	14400bps	25dB
	12000	22
	9600	19
	7200	17
V.29/27ter	9600	21
	7200	18
	4800	15
	2400	9

2) C2 line - maximum noise that the modem had a successful three-page transmission. Under this line condition, the modem showed only a 1~3 dB degradation compared to the ideal channel.

V.17	14400	26
	12000	24
	9600	21
	7200	20
V.29/V27ter	9600	22
	7200	21
	4800	18
	2400	12

3) 3002 conditioned line. The same test was performed.

V.17	14400	27
	12000	27
	9600	26
	7200	26
V.29/V.27ter	9600	27
	7200	26
	4800	22
	2400	19

The maximum signal to noise ratio for a bit-error rate of 1 E-5 (lower is better):

Modem A: ~24.3dB

Modem B: ~22.6dB

Commetrex: ~21.8dB

This means that Commetrex modems can operate on a signal containing higher noise and still achieve the same bit-error rate.