The MT8840 is a carrier over voice modem which allows simultaneous transfer of voice and data over a single pair of wires. Data is transferred on an amplitude shift keyed (ASK) 32 kHz carrier. On-chip filters remove voice frequency signals from the received composite voice and data signal prior to demodulation. The modulating signal is a bit stream with a typical data rate of 2 kbps. In addition, the device contains a two tone warbler which functions as a telephone ringer. The device is fabricated in Zarlink's double-poly ISO2-CMOS technology utilizing switched-capacitor techniques.
