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.

Features

Benefits

TMS320C6000 Resource Utilization

ModulePerformance (mega-cycles/sec)Code Space (bytes)Constants and tables (bytes)Per-Instance Memory(bytes)
Total5.3 (V.17R)49,656*14,938*
V.17 transmitter3.75,9845,036472
V.17 receiver5.328,0007,1582076
V.27ter/V.29 transmitter**4.6 (V.27: 4.0)6,9044,228504
V.27ter/V.29 receiver**5.1 (V.27: 5.5)23,2643,9961632
V.21 transmitter2.13,4882,080192
V.21 Receiver3.94,1601,804200
*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.

‘C5400 Resource Numbers

V.21 Rec798 words
V.21 Xmit451 words
V.17 Rec3030 words
V.17 Xmit815 words
V2X Rec2139 words
V2X Xmit809 words
FAXC47 words
FMDP1294 words
Table(.data):
V21R31 words
V17R518 words
V17T724 words
V2XR592 words
V2XT675 words
FAXC270 words
FMDP58 words
.const:FMDP36 words
.bss:FMDP10 words
Total:12,297 words
MIPS:11.98 (10ms buffers)
Object memory/port:712 (16-bit) words

Bit-Error Rate performance

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.1714400bps25dB
1200022
960019
720017
V.29/27ter960021
720018
480015
24009

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.171440026
1200024
960021
720020
V.29/V27ter960022
720021
480018
240012

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

V.171440027
1200027
960026
720026
V.29/V.27ter960027
720026
480022
240019

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

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

Ordering Information

V.21 on ‘C54/C6x-1/-260105
V.27 on ‘C54/C6x-1/-260108
V.29 fax on C6x-1/-260109
V.17 fax/V.33 on C6x-1/-260111
Fax Modem Bundle-1/-260112