The CMX878 is a line-powered multi-standard modem for use in telephone based information and telemetry systems. It provides the building blocks for interfacing to the telephone line without the need for a transformer - this is the Data Access Arrangement (DAA) allowing for the coupling of data signals to and from the line; it can also detect Ringing and Line Reversals. Provision is made for the conditioning and monitoring of other aspects of the telephone line this includes the gyrator/loop current, line impedance control, and line voltage measurement. A complete line interface can be implemented using low cost external components. Very low power consumption and built-in power management makes the CMX878 suitable for telephone line power usage. Furthermore the microcontroller can be de-powered whilst awaiting the detection of a Ring, Line Reversal, or WAKE pin event. Control of the device is via a simple high speed serial bus, compatible with most types of C serial interface. Data transmitted and received by the modem is transferred over the same serial bus. The CMX878 is available in 28-pin SOIC, SSOP and TSSOP packages.