General Description
The CMX624 contains a Bell 202 and V.23 compatible FSK modem. This device is capable of duplex operation at 1200/75bps or 1200/150bps over a 2-wire line interface. It is also capable of 1200/1200bps over a 4-wire line interface. This device also contains a flexible FSK data UART, a receive FSK or Call Progress Tone energy detector, a 2100Hz detector, a DTMF generator, a Tx line driving buffer amplifier, a telephone line Ringing Signal or Line Voltage Reversal detector and a 3.579545MHz Xtal oscillator. These functions are controlled via a serial interface to the µC, which also carries the transmit and receive FSK modem data.

Features
• Bell 202 and V.23 Compatible Modem
• 1200bps Full duplex Operation (2 or 4 Wire)
• Software Adjustable Tx and Rx Levels
• Programmable Group Delay Equalizer
• Answer/Originate Tone Generator/Detector
• Call Progress Tone Detection
• Integrated DTMF Encoder
• Line Reversal and Ring Detector
• Simple Serial Control Interface
• Hook Switch Relay Driver
• Zero-Power Standby Mode
• 3.0 to 5.0V Operation

Applications
• Telephone Telemetry Systems
• Remote Utility Meter Reading
• Security Systems
• Payphones
• Cable-TV Set Top Boxes
• Industrial Control Systems
• Electronic Cash Terminals
• Vending Machines