25 Feb
2003
25 Feb
'03
9:55 a.m.
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.
Ahh, That explains why it was allways fussy about signal levels. The data
sheet said that it could do it, and I had to alter the level of the
BELL/CCITT pin.