Centrex Modem
by HotHaus Technologies

Software Overview

The HotHaus Centrex modem software module provides all of the data control and voice signaling 
required for Centrex lines. It is compliant with the Northern Telecom NIS 106-1 Centrex modem 
specification. It is available standalone or as a device driver for HausWare.
The HotHaus Centrex Modem uses the full 16-bit Centrex message format. The host application (or 
HausWare) will provide the appropriate settings for the transmit message, and is responsible for 
parsing the received message passed to it from the Centrex Modem.
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. Centrex 
Modem has been written entirely in assembly.

Features and Benefits

•	Less than 0.5 MIP and 1K Word of ROM are required
•	Parity check, collision detect, and retransmission for collision recovery
•	Asynchronous half-duplex 1-kbps ASK data signaling channel centered at 8 KHz
•	Fully re-entrant, each extra port requires only small additional RAM space
•	Compliant with Northern Telecom's NIS 106-1 Centrex modem specification

Processor and System Requirements

Runs on Texas Instruments TMS320C5x family of DSPs.

Usage Limitations or Performance Considerations

None

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