The CMX867A is a multi-standard modem for use in telephone based information and telemetry systems.
Control of the device is via a simple high speed serial bus, 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 allow unformatted synchronous data to be received or transmitted as 8-bit words.
A high quality DTMF decoder with excellent immunity to falsing on voice, and a standard DTMF encoder are included. Alternatively, these blocks can be used to transmit and detect user-specific, programmed single and dual-tone signals, call-progress signals or modem calling and and answering tones.
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 Hook Switch Relay Drive output and a Ring Detector circuit which
continues to function when the device is in the Powersave mode, providing an interrupt which
can be used to wake up the host µController when line voltage reversal or ringing is detected.
