Wasn't that chip used in the Tandy TRS-80 Model
100 machines.
I thought the M100 uses the 14412 chip...
I remember playing with the Band Pass filters to convince the TRS-80 to work
with CCITT tones, instaed of the Bell tones that were used in USA. That was
a while ago
IIRC, the 14412 didn't demodulate CCITT tones reliably at 300 baud. The
better-designed UK modems that used this chip at all used it for the
modulator only and used something like an XR2211 for the demodulator.
-tony