User guide

232 RealCT Direct API Developer Guide
Appendix A: T1 Line Protocols
Table 40 shows the pattern of bits transmitted when the station
calls the CO.
Table 40. Loop Start: station Calls CO
In the Loop Start protocol, both ends transmit 01 in the idle
state. When the station calls the CO, the CO continuously sends
a 01 signal. The station seizes the line using a 11 signal, then
disconnects by returning to the idle 01 state.
When the station disconnects, RHT_DISCONNECT or
RHT_ON_HOOK terminates immediately, since there is no bit
change that the CO needs to perform.
When the application initiates a call, it waits for a dial tone,
then dials digits. There is no signal from the CO to acknowledge
the outgoing call, indicate an answer by the called party, or
indicate that the called party disconnected.
If the network you are connected to accepts call transfers, the
HookFlash duration is determined by
RDG_LOCAL_FLASH_DUR.
Status CO Station Timing Parameter
Idle 01 01
Seizure 01 <-- 11
Dialtone from CO 01 11
Digits from Station 01 11
Answer 01 11
Conversation 01 11
Station disconnects 01 <-- 01
HookFlash 01 <-- 11/01/11 RDG_LOCAL_FLASH_DUR