User guide

August 2001 231
Loop Start
Loop Start
Tables 39 and 40 show the pattern of bits transmitted by the
CO and the station in the Loop Start protocol. Table 39 shows
the pattern when the CO calls the station.
Table 39. Loop Start: CO Calls Station
In the Loop Start Protocol, both ends transmit 01 in the idle
state. When the CO calls the station, it transmits 00 then
returns to 01 when the station sends the 11 answer signal. The
station disconnects by returning to the 01 state.
The CO indicates a ring pattern by toggling the B bit from 0 to
1. The cadence is the same as the ring for analog lines, 2000 ms
ring present, 4000 ms ring absent, where 0 indicates ring
present and 1 indicates ring absent.
The CO does not send digits to the station unless the line is
configured to provide Caller ID information. There is no
information when the calling party disconnects.
Status CO Station Timing Parameter
Idle 01 01
Seizure: Ringing 00 --> 01
Answer 01 <-- 11
Conversation 01 11
Station disconnects 01 <-- 01
HookFlash 01 <-- 11/01/11 RDG_LOCAL_FLASH_DUR