The MT8880C/C-1 is a monolithic DTMF transceiver
with call progress filter. It is fabricated in Mitel’s
ISO2-CMOS technology, which provides low power
dissipation and high reliability. The DTMF receiver is
based upon the industry standard MT8870
monolithic DTMF receiver; the transmitter utilizes a
switched capacitor D/A converter for low distortion,
high accuracy DTMF signalling. Internal counters
provide a burst mode such that tone bursts can be
transmitted with precise timing. A call progress filter
can be selected allowing a microprocessor to
analyze call progress tones. A standard
microprocessor bus is provided and is directly
compatible with 6800 series microprocessors. The
MT8880C-1 is functionally identical to the MT8880C
except for the performance of the receiver section,
which is enhanced to accept and reject lower signal
levels.