PairGain PG-Flex, Manual

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PG-Flex System Overview
6
COT Channel Units
PG-Flex channel units interface between subscriber services and the system’s internal PCM bus.
All channel units include status indicators for each circuit supported on the channel unit and may
be “hot plugged” without affecting system operation. A number of different channel units are
available based on the service required.
COT POTS Channel Units
COT POTS channel units provide the analog-to-digital interface between PG-Flex’s internal PCM
bus and the CO switch. LEDs display the status of each subscriber channel, and indicate channel
unit fault conditions. Channel units provide a metallic connection to the metallic bypass pair for
subscriber drop testing. On hook transmission is provided to support CLASS services.
The 8-channel POTS units for PG-Flex support eight analog interfaces at both the CO and RT
locations. Three channel units are required for a 24-channel system. The channel units provide the
following features:
• converts analog signals to 64 kbps (µ-Law or A-Law) PCM digital format
• detects ringing voltage
• detects 12 kHz and 16 kHz meter tones
• detects forward disconnect
• detects subscriber drop metallic access signal
• provides loop closure
• provides on-hook transmission to support CLASS services
A status LED associated with each line indicates whether the line is off-hook, idle, ringing, or being
tested. A common fault LED indicates that a general fault has been detected on the unit and that
the unit should be replaced.
Metallic access relays provide a metallic connection to “look-in,” “look-out,” and “bridge” on each
line circuit. Metallic access points appear on the COT Alarm or PGTC Interface Units. Metallic
access connections to a specific line circuit are made through the maintenance terminal or by the
CO switch applying the appropriate voltages on the subscriber line.