CML - Wireline Data and Telephony - CMX860

The CMX860 is a flexible, low-power Telephone Signalling Transceiver IC, designed for use in a wide range of line-powered telephone equipment.
The IC combines the functions of a DTMF encoder and decoder, V.23 and Bell 202 modulator and demodulator plus call progress circuitry with analogue switching between line and phone interfaces.

Ring detection, local phone off-hook detection and a relay driver for line hook-switch operation are also provided under the control of 'C-BUS'. The ring and hook detectors operate whilst the remainder of the IC is powersaved, generating an interrupt to wake-up the host µC when further processing or signalling is required.

All on-chip functions and switching arrangements are controlled via the C-BUS command/data serial bus.
The CMX860 is designed to operate at 2.7V and utilises CML’s low power DTMF decoder and V.23 modem technology.

Block Diagram


  • V.23 1200/75 b/s FSK Tx/Rx
  • Bell 202 1200/150 b/s FSKTx/Rx
  • Tx/Rx DTMF Tones
  • Line and Phone Complimentary Drivers
  • Call Progress Decoder
  • Simple 'C-BUS' Serial Interface
  • Low Power Operation with Standby Mode


  • Least Cost Routers
  • Vending Machines
  • Internet Appliances
  • Home Management Systems
  • Remote Meter Reading
  • Alarm Systems
  • Cable System TV Set-Top Boxes

Supply Requirement:

  • 2.7 to 5.5 V power supply