Specifications

Si3220/25 Si3200/02
Preliminary Rev. 1.3 55
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3.15.1. Ringtrip Timeout Counter
The Dual ProSLIC incorporates a ringtrip timeout
counter, RTCOUNT, that will monitor the status of the
ringing control. When exiting ringing, the Dual ProSLIC
will allow the ringtrip timeout counter a sufficient amount
of time (RTCOUNT x 1.25 ms/LSB) for the mode to
switch to On-hook Transmission or Active. The mode
that is being exited to is governed by whether the
command to exit ringing is a ringing active timer
expiration (on-hook transmission) or ringtrip/manual
mode change (active mode). The ringtrip timeout
counter ensures ringing is exited within its time setting
(RTCOUNT x 1.25 ms/LSB, typically 200 ms).
3.15.2. Ringtrip Debounce Interval
The ac and dc ring trip debounce intervals can be
calculated based on the following equations:
RTACDB = t
debounce
(1600/RTPER)
RTDCDB = t
debounce
(1600/RTPER)
Figure 27. Ring Trip Detect Processing Circuitry
Input
Signal
Processor
Digital
LPF
+
_
AC Ring Trip
Threshold
RTPER
LFS
ILOOP
RTACTH
Debounce
Filter_AC
Interrupt
Logic
RTRIPS
RTP
RTRIPE
+
_
DC Ring Trip
Threshold
RTDCTH
Debounce
Filter_DC
RTACDB
RTDCDB
Digital
LPF
Full Wave
Rectifier