CPC7581
Table 5. Make-Before-Break Operation (Ringing to Idle/Talk Transition)
Ring
Return
Switch
3
Closed
Open
Ring
Access
Switch
4
Closed
Closed
Break
Switches
1 & 2
Input
5V
0V
TSD
5V/Float
5V/Float
State
Ringing
Timing
-
Open
Make-before-break SW4 waiting for next zero current Closed
crossing to turn off. Maximum
time is half of ringing. In this
transition state, current that is
limited to the dc break switch
current limit value will be sourced
from the ring node of the SLIC
0V
5V/Float
Idle / Talk
Zero cross current has occurred
Closed
Open
Open
Table 6. Break-Before-Make Operation (Ringing to Idle/Talk Transition)
Ring
Return
Switch
3
Closed
Open
Ring
Access
Switch
4
Closed
Closed
Break
Switches
1 & 2
Open
Open
Input
5V
5V
TSD
5V/Float
0V
State
Ringing
All Off
Timing
-
Hold this state for <=25ms.
SW4 waiting for zero current to
turn off.
0V
0V
0V
All/Off
Zero current has occurred
SW4 has opened
Release Break Switches
Open
Open
Open
Open
Open
5V/Float
Idle/Talk
Closed
Rev. 2
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