Calling Line Identifier
CMX602B
longer (88 to 110ms) Tone Alert signal employed by BT for on-hook applications will not necessarily cause
IRQN to go low.
See section 1.7.1 for definitions of Tton, Ttoff and TqCAS
Figure 6 : Tone Alert Detector operation
1.5.8 Ring or Line Polarity Reversal Detector
These circuits are used to detect the Line Polarity Reversal and Ringing signals associated with the Calling
Line Identification protocol.
Figure 7 illustrates their use in a typical application.
Figure 7 : Ring or Line Polarity Reversal operation
ã 1999 Consumer Microcircuits Limited
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D/602B/1