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SCP-PLL724-010-04H
O
VERVIEW
This practice describes the ADC
interfaces for one POTS and one ISDN interface between a PG-Plus RT and subscribers.
D
ESCRIPTION AND
A ADC application, consisting of one COTS, one COLU and one RT, (see
transport of multiple DS0, over a single, unconditioned wire pair using HDSL technology. Using existing cable,
PG-Plus provides for higher bandwidth needs of residential and business customers by providing multiple POTS
interfaces on a single HDSL twisted-pair wire.
PG-Plus COT Shelf
Alarm relays
Remote ACO
Dumb
Terminal
The COLU uses ADC's HDSL technology to provide digital transmission rate without the need for repeaters, loop
conditioning, or pair selection. The COLU is an ideal solution to ISDN and POTS deployment over a limited cable
plant. The COLU can be installed in the PCS-718 19-inch or the PCS-719 23-inch COTS. The COLU operates in
the standalone mode with no other COTS circuit cards required. Advanced features such as performance
monitoring, alarm reporting, and testing requires the addition of the PAU. Line power is provided to the RT by
the COLU.
The COLU performs the interface functions between the analog POTS circuits of the CO switching system by
mapping one POTS lines onto one DS0 for transmission to the RT on the HDSL pair. The COLU performs the
interface functions between the ISDN circuits of the CO switching system and the internal digital PCM bus. The
COLU maps one ISDN line onto three DS0 for transmission to the RT on the HDSL pair. To obtain maximum
reach, the HDSL line to the RT is operated at the minimum rate to support the payload.
M
F
ETALLIC
ALLBACK
Metallic fallback provides a direct connection from the CO to one subscriber under fault conditions. Service is
provided to the subscriber assigned to the first POTS line in the affected system. At the RT, the system exits
metallic fallback and attempts to synchronize if either POTS or the HDSL Tip to Ring pair is shorted for at least
3 seconds, and then released for at least 3 seconds. Otherwise, the COLU checks for the presence of an RT every
5 minutes. If an RT is present, the system begins HDSL synchronization acquisition.
Relays in the COLU and RT provide a path for SDT and metallic fallback operation. These relays are used to
establish a circuit to POTS # 1 during fault conditions and to provide for drop testing of the selected subscriber
line from the CO location.
PLL-724 List 1
®
®
PG-Plus
1 POTS/1 ISDN COLU, PLL-724 List 1, a COLU that provides
F
EATURES
C
O
HDSL Pair
L
U
Other RTs
Figure 1. Typical System Application
January 6, 2003
Description and Features
Figure
1) provides bidirectional
POTS
PG-Plus RT
ISDN
1
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