CMX644A Datasheet | Consumer Microcircuits Limited

V.22 and Bell 212A Modem D/644A/6 June 2000 Provisional Issue Features - - - - - - V.22/Bell 212A patible Modem Integrated DTMF Encoder Call Progress/Accurate Answer Tone Detection Line Reversal and Ringing Detector Low Power Operation (2.7V) Fully Integrated UART Functions Applications - - - - - - Telephone Telemetry Systems Remote Utility Meter Reading Security Systems/Cash Terminals Industrial Control Systems Pay-Phones Cable TV Set-Top Boxes Brief Description The CMX644A V.22 modem is intended for use in any telephone based information and telemetry system with low power requirements. Using V .22 signalling, fast call set up times and robust error resistant transmission can be implemented by efficient low power circuits. The circuit can operate at 1200b/s full duplex over 2 -or 4wire circuits. Control of the device is via a simple high speed serial bus and data m ay be optionally formatted by the on -chip UART. This allows easy interfacing to a host µController. The data transmitted and received by the modem is also transferred over the same high speed serial bus. In addition to V .22, support is included to meet t he Bell 212A standard. The integrated DTMF encoder can be used as part of the dial out function. All 16 DTMF binations are available along with a single tone ‘melody’ mode. The answer tone generator/detector and call progress tone detectors included on the CMX644A make the setup of a telephone call a simple matter for the host µController. In many data collection and telemetry systems low power consumption is important. The CMX644A Features a ‘Zero Power’ standby mode. Whilst in standby, the device can still detect a ringing voltage or line voltage reversal. The CMX644A can operate on a supply voltage between 3.0V and 5.5V across the full temperature range of -40°C to +85°C. A low impedance pull down output is provided for a hook relay. The CMX644A is pin patible with the CMX624 V23/Bell 202 modem also from CML. © 2000...