The CMX649 Adaptive Delta Modulation (ADM) Voice Codec provides full duplex ADM, companded (/A-law) PCM and linear PCM codec and transcoder functions for cost effecive, low power, wireless voice applications. Selectable modes and algorithms support many applications. Robust ADM coding (e.g. CVSD) reduces host protocol and software burdens, eliminating forward error correction, framing protocols and algorithm processing. Dual transcode/decode mode supports multichannel applications. Integrated filter responses adjust independent of 16kbps to 128kbps codec data rates. Codec sample clocks are externally applied or internally generated. High performance analog interfaces and sidetone include digital gain controls. Encoder and decoder voice activity detectors support powersaving. The CMX649 ADM Voice Codec supports 2.7V to 5.5V operation and is available in 20-pin SOIC (D3) and TSSOP packages (E3) packages.