Calling Line Identifier with VMWI
CMX612
2.
3.
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 CMX612 switched to FSK Receive mode to be ready to receive the FSK
data, doing this will also clear the IRQN output.
The CMX612’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 10b : Flow Chart for Off-hook operation of CMX612
ã 2002 Consumer Microcircuits Limited
18
D/612/3
CMLMICRO [ CML MICROCIRCUITS ]
