COMMUNICATION SEMICONDUCTORS
DATA BULLETIN
Features
• V.23 1200/75bps FSK Transmit and Receive
• DTMF/Tones Transmit and Receive
• Line & Telephone Complementary Drivers
• Call Progress Decoder
• CAS Tones Detection and Generation
• Simple ‘C-BUS’ Serial Interface
• Low Power Operation
• ‘Powersave’ Standby Mode
CMX860
Telephone Signaling
Transceiver
ADVANCE INFORMATION
Applications
• Least Cost Routers
• Vending Machines
• Alarm Systems
• Home Management Systems
• Remote Meter Reading
• Internet Appliance Applications
• Cable TV Set-Top Boxes
• Advanced Feature Phones
LINE
LINE
INTERFACE
PHONE
PHONE
INTERFACE
TX USART / FSK MODULATOR
& TONE / DTMF GENERATOR
RX USART / FSK RECEIVER
CALL PROGRESS, CAS &
ANSWER TONE DETECTOR
DTMF DECODER
RING DETECTOR
HOOK DETECTOR
RELAY DRIVER
CMX860
'C-BUS'
SERIAL
INTERFACE
HOST
µC
The CMX860 is a flexible, low power Telephone Signaling 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 modulator and demodulator plus call
progression circuitry with analog switching between line and phone interfaces. Ring detection, local phone off-
hook detection, and a relay for line hook-switch operation are also provided under the control of C-BUS. The
ring and hook detectors operate while the remainder of the IC is powersaved, generating an interrupt to wake-
up the host µC when further processing or signaling is required.
All on-chip functions and switching arrangements are controlled via a serial bus (C-BUS). The CMX860 is
designed to operate at 2.7V and utilizes MX-COM’s low power DTMF decoder and V.23 modem technology.
The CMX860 is available in 28-pin SSOP (CMX860D6) and 28-pin SOIC (CMX860D1) packages.
¤2000 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480222.001
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.