V.22bis Data Modem
by HotHaus Technologies

Software Overview

The HotHaus V.22bis data modem software module is fully compliant with the ITU-T V.22bis 
recommendation, and provides for 2400-bps data modem communications. It is available stand alone or 
as a PSTN line service for HausWare. V.22bis also includes V.25 signaling. 
The V.22bis transmitter will receive 8- or 7-bit bytes from a host program and output modulated 
samples to a codec interface routine. The V.22bis receiver will receive incoming samples from a 
codec interface routine, demodulate them, and output the received 8- or 7-bit byte data to the host 
function. 
A well-written and thorough Technical Reference Manual is available describing the V.22bis data 
modem and how to interface to it via C or assembly. Example C and Psuedocode are included in the 
manual.
All HotHaus software modules are all designed to operate with minimal MIPS and memory. V.22bis has 
been written entirely in assembly.

Features and Benefits

•	4.5 MIPS and 5K Words of ROM are required
•	BER of 10-6 with an SNR of 17 dB
•	Fallback support to V.22 (1200 bps)
•	Fully re-entrant, each extra port requires only small additional RAM space
•	Linear PCM and m-law support

Processor and System Requirements

Runs on Texas Instruments TMS320C5x family of DSPs.
Operates with either  8-KHz or 9.6-KHz sampling rates.

Usage Limitations or Performance Considerations

None

Algorithm Verification

Tested against commercial modems

Availability

Immediately on 'C5x. Can easily be ported to 'C2xx and other TI fixed-point DSPs.

Company Background and Contact Information

HotHaus are experts in TI fixed-point DSP software algorithms for telecommunications. HotHaus' 
algorithms are ideally suited for advanced telecommunications products such as feature phones, PBX 
or key systems, and general computer telephony products.
HausWare is the flagship of the company's product line, and it provides a complete DSP software 
system architecture specifically for telecommunications products. HausWare is the key to HotHaus 
providing a cost-effective software system solution to our customers.

Contact:	Dan McCallum
		HotHaus Technologies Inc.
		1B - 7218 Progress Way
		Delta BC Canada
		V4G 1H2
		(604) 946-0060
		fax: (604) 946-5811