Brief Description
The CMX869 is a multi-standard modem for use in telephone based information and telemetry systems. It can transmit and detect standard DTMF and modem calling and answer signals or user-specific programmed single or dual tone signals. A general purpose Call Progress signal detector is also included.
Flexible line driver and receive hybrid circuits are integrated on chip, requiring only passive external components to build a 2 or 4-wire line interface.
The device also features a software controlled hook switch Relay Drive output and a Ring Detector circuit, which continue to function when the device is in the Powersave mode. When a line voltage reversal or ringing signal is detected, the Ring Detect Circuit can provide an interrupt which can be used to wake up the host µController.
Control of the device is via a simple high speed serial bus that operates in normal and Powersave modes, and is compatible with most types of µC serial interface. The data transmitted and received by the modem is also transferred over the same serial bus. On-chip programmable Tx and Rx USARTs meeting the requirements of V.14 are provided for use with asynchronous data and to allow unformatted synchronous data to be received or transmitted as 8-bit words or as a HDLC packet.

FEATUREs
· V.32 bis/V.32/V.22 bis/V.22 automodem. (14400, 12000, 9600, 7200, 4800, 2400, 1200 bps duplex)
· V.23 (1200/75, 1200/1200, 75, 1200 bps FSK)
· Bell 202 (1200/150, 1200/1200, 150, 1200 bps FSK)
· V.21 or Bell 103 (300/300 bps FSK)
· DTMF/Tones Transmit and Receive
· ‘Powersave’ Standby Mode

APPLICATIONs
· Telephone Telemetry Systems
· Remote Utility Meter Reading
· Security Systems
· Industrial Control Systems
· Electronic Cash Terminals
· Pay-Phones
· Cable TV Set-Top Boxes