950-734-100-01, Revision 01
Product Overview
PLL-734 List 1
December 18, 1998
1
P
RODUCT
O
VERVIEW
This practice describes the PairGain
®
PG-Plus™ PLL-734 List 1, a COLU that provides interfaces to two 2 POTS
RTs (PRL-784) for four POTS subscribers.
D
ESCRIPTION
AND
F
EATURES
A PG-Plus application (see
Figure 1
) provides bidirectional 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. A typical application of a PG-Plus system consists of:
•
One COTS
•
One COLU
•
Two RTs
Figure 1.
Typical PG-Plus Application
The COLU can be installed in the PCS-718 or the PCS-719 COTS. The COLU operates in standalone mode with
no other COTS circuit cards required. Advanced features such as performance monitoring, alarm reporting, and
testing require the addition of the PAU or the PMU. Line power is provided to the RT by the COLU.
Metallic fallback provides a direct connection from the CO to one subscriber under fault conditions. Provisional
service is provided to the first POTS subscriber on the affected system. At the RT, the system exits metallic
fallback and attempts to synchronize if either the first 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
five 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.
POTS-1A
POTS-2A
POTS-1B
POTS-2B
COLU
COTS
HDSL Pair A
HDSL Pair B
RT-A
RT-B
POTS-1A
POTS-2A
POTS-1B
POTS-2B