Following is a sample analog protocol on the Exchange Terminate side that will provide a line reversal of 1 second:-
Current State / Line Condition------------------------Condition-------------------------------------------Next State / Line Condition
Idle / Normal (LCF)---------------------------------------Loop Closed / 200 ms-------------------------Seize / Battery Reversal (RLCF)
Seize / Battery Reversal (RLCF)-----------------------Loop Closed / 1000 ms-----------------------Answer / Normal (LCF)
Answer / Normal (LCF)----------------------------------Loop Open / 200 ms----------------------------Idle / Normal (LCF)