GAO Modem Library
by GAO Research & Consulting Ltd.

Software Overview

GAO Modem Library consists of implementations of the data pump of the ITU modem standards, V.21, 
V.22, V.22bis, V.32, V.32bis, V.34, and Bell modem standards Bell 202 and Bell 212A.

Standard
Maximum Data Rate (bps)
ITU V.21
300
ITU V.22
1,200
ITU V.22bis
2,400
ITU V.32
9,600
ITU V.32bis
14,400
ITU V.34
28,800
Bell 202
1,200
Bell 212A
1,200

Features and Benefits

•	Full-duplex operation
•	Advanced techniques used for high-speed modem: adaptive equalization, echo cancellation, Trellis 
coding, and Viterbi decoding

Processor and System Requirements

•	Devices supported: `C3x, `C5x, `C54x
•	Algorithm category: Telecommunications
•	Required:
Function
Average MIPS
Data Memory
Program Memory
ITU V.21 (Rx and Tx)
3.5
0.7 k
0.7 k
ITU V.22 (Rx and Tx)
6.0
1.0 k
1.7 k
ITU V.22bis (Rx and Tx)
7.0
1.4 k
1.9 k
ITU V.32 (Rx and Tx)
12.0
1.7 k
2.0 k
ITU V.32bis (Rx and Tx)
14.0
3.0 k
3.5 k
ITU V.34 (Rx and Tx)
33.0
17.0 k
15.0 k
Bell 202
5.0
0.9 k
1.6 k
Bell 212A
6.0
1.0 k
1.8 k

Algorithm Verification

•	The modem software implementations follow the specifications of the ITU standards. Performance 
and acceptance tests are performed against popular modem cards.

Availability

•	The software is available now and demonstration is available at GAO's offices in Toronto, Canada.

Company Background and Contact Information

GAO Research & Consulting Ltd. is an established international supplier of DSP algorithms, 
software, and systems for the telecommunications market. It provides a complete line of telephony, 
fax, and modem solutions. Its products have been widely reported by over 30 leading publications in 
the industry.
GAO currently employs about 20 DSP engineers. It was founded in 1991 and has been managed by Dr. 
Frank X.Y. Gao.
Contact:	Dr. Frank X.Y. GAO, CEO
		GAO Research & Consulting Ltd.
		55 Nugget Avenue, Unit 204
		Scarborough,  Toronto
			Ontario, Canada M1S 3L1
		(416) 292-0038
		Fax: (416) 292-2364
		e-mail: gao@io.org
		www: http://www.io.org/~gao