Calling Line Identifier
CMX602A
2.
The IRQN output going low when in Tone Alert Detect mode indicates that a CAS has been detected.
The local handset and keypad should then be muted as required by the Bellcore specification and the
CMX602A switched to FSK Receive mode to be ready to receive the FSK data, doing this will also
clear the IRQN output.
3.
The CMX602A’s DET output should be monitored for a period of 50ms after changing to FSK Receive
mode, before sending the ACK signal, and the transaction abandoned if the DET output goes high
during this time, which would be the case if a false CAS detect had been caused by far end speech.
Figure 9b : Flow Chart for Off-hook Operation of CMX602A
ã 1998 Consumer Microcircuits Limited
18
D/602A/4
CMLMICRO [ CML MICROCIRCUITS ]
