Revision 01
July 30, 1999
Section 363-703-142
FLC-703, List 4B
PairGain Engineering - Plant Series
Page 5
5.2.1
Loop start idle condition is a Ring lead negative and Tip lead positive from the Central Office
Terminal (COT) with the same conditions out of the RT toward the subscriber. The following occurs
when the calling line goes off-hook:
•
loop current flows and is detected by the FRC-753
•
FLC-703 receives an off-hook signal from the RT
•
FLC-703 generates an off-hook signal to the Central Office (CO) to begin current flow
•
CO sends dial tone
•
FRC-753 recognizes dial pulses or Dual Tone Multi Frequency (DTMF) signaling, from the
subscriber and forwards these as loop current breaks, dialing or DTMF signaling, at the CO
The following occurs for an incoming call:
•
FLC-703 detects a ringing signal from the CO
•
FLC-703 signals the FRC-753 which then connects ringing to the subscriber
•
subscriber line goes off-hook and the FRC-753, via the FLC-703, signals the CO to disconnect
ringing and establish an audio path
5.2.2
Ground start idle condition is a Tip lead open and Ring lead negative into the CO and Tip lead open
and Ring lead negative at the RT. The following occurs when a PBX requests service for an
outgoing call by grounding the Ring lead at the RT:
•
FRC-753 signals the FLC-703
•
FLC-703 operates a Ring ground relay that requests dial tone from the CO (this makes the
circuit busy, or seizes it, for outgoing calls to prevent others from using it, i.e., prevents glare
where different users can seize a line at the same time)
•
CO sends dial tone and grounds the Tip to signal the PBX to begin dialing
•
FLC-703 detects Tip ground, closes the loop between Tip and Ring, and signals the FRC-753 to
send Tip ground to the PBX
•
PBX removes the original Ring ground condition and completes the loop (Tip and Ring)
The following occurs for an incoming call:
•
FLC-703 detects a ringing signal from the CO, along with Tip ground
•
FLC-703 signals the FRC-753 which then connects Tip ground and ringing to the PBX
•
PBX goes off-hook and the FRC-753, via the FLC-703, signals the CO to disconnect ringing and
establish an audio path
5.2.3
When caller ID (a CLASS feature) is activated, the CO generates a signal to the subscriber between
the first and second bursts of the ringing signal only (i.e., PG-Flex supports on-hook transmission).
The forward-disconnect function releases a called line that was left on hold or an answering set that
requires a loop open to be able to turn off.
Summary of Contents for 150-1303-42
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