Overview
363-703-131-01, Revision 01
4
July 30, 1999
FLC-703 List 3A
FLC-703 F
UNCTIONS
The FLC-703 Channel Unit provides eight POTS channel interfaces to the CO switch. Each FLC-703 detects:
•
forward battery
•
ringing voltage
C
IRCUIT
O
PERATION
The following paragraphs define the FLC-703 circuit operation. Each FLC-703 circuit has an associated LED that
indicates when the line is off-hook, idle, ringing, or under test. See
Figure 1 on page 2
.
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, by means of the FLC-703, signals the CO to disconnect
ringing and establish an audio path
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 (for example, 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 FLC-703
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