22 Apr
2014
22 Apr
'14
7:29 a.m.
Can you run thru the asterisk POTS line cars with the
frequencies,
etc, or do those only handle voice grade frequencies?
For 300 baud, the modulation scheme was normally simple phase-coherent
FSK. The send end used 1070Hz and 1270Hz, with the receive end using
2025Hz and 2225Hz - this according to the Wikipedia page "Modem", which
also notes that "These frequencies were chosen carefully; they are in
the range that suffers minimum distortion on the phone system and are
not harmonics of each other").
Any voice-compatible channel _should_ work fine for them.
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