Communications Controller
CMX850
C. CAS Tone Alert detected and interrupt generated, which causes the CMX850 to mute near
end voice, and check that no further CAS tones are detected for 50ms (to minimise falsing)
D. Modem set up to send ACK to Central Office to signal readiness to receive FSK data.
E.
Central Office recognises ACK and sends FSK data. The CMX850 is set up to receive the
FSK data.
F.
The Transaction is complete. The CMX850 unmutes the near voice, and reverts back to its
origianal mode, while the central office unmutes the far end voice, normal conversation
returns.
Figure 7c Typical off-hook (Type 2) message transaction
© 2003 CML Microsystems Plc
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