950-779-115-02, Revision 02
Overview
PRL-770 and PRL-779 List 1E and 2E
March 17, 2000
1
O
VERVIEW
The PairGain
®
PG-Flex
Plus
™ PRL-770 List 2 E and PRL-779 List 1 E, provides interfaces for LS/GS POTS
subscribers. The PRL-779 supports Loop Start and Ground Start (LS/GS) POTS, allows Tip and Ring polarity
reversal for support of Millennium pay phones, and implements TR-08 channel testing. The PRL-770 is a 4 LS
Indoor Remote Terminal Enclosure, and the PRL-779 is a 6 LS/GS Indoor Remote Terminal Enclosure.
A PG-Flex
Plus
system provides bidirectional transport of multiple DS0s over a single, unconditioned wire pair
using HDSL technology. Using an existing cable, PG-Plus provides for higher bandwidth needs of residential and
business customers by providing multiple LS/GS interfaces on a single HDSL twisted-pair wire.
shows
a minimally configured PG-Plus application that consists of one COT shelf, one COLU, and one RT.
Figure 1.
Typical PG-Plus Application
Each COLU housed in a COT shelf interfaces with a corresponding RT. LS/GS or digital lines from a CO
switching system connect to the COT shelf and are sent by means of the COLU and the HDSL wire pair to an RT.
As an example, a 23-inch COT shelf can interface with sixteen different RTs providing up to six LS/GS lines each,
for as many as 96 subscriber lines. The COT shelf operates on standard -48 Vdc CO battery and supplies power
to the RT, eliminating the need and expense of providing local power at the RT. A PG-Plus system with HDSL
transmission and line-powered RTs results in fast, cost-effective solutions to LS/GS deployment over minimal
copper facilities.
I
NTEGRATED
C
HANNEL
T
ESTING
The LS/GS RT supports channel testing as described in TR-TSY-000008 and TR-TSY-000465 when the PG-Plus
system is configured to interface to a TR-08 compliant digital switch. During the channel test, a sequence of
hand-shaking messages and tones are exchanged between the PG-Plus system and the switch, and the LS/GS RT
responds by applying the appropriate absorptive (600
) or reflective (0 ) test terminations to the remote channel
under test, thus allowing for both transmission and signalling tests to be performed on that specific channel. The
transmission tests verify the transmission parameters, such as channel loss, return loss, and idle channel noise are
within the required limits. The signalling tests, that consist of off-hook detection and a ringing test, ensure that the
channel can detect and produce the correct signalling states. In addition to the channel testing, the LS/GS RT
works in conjunction with the switch to provide subscriber drop testing.
When using a 23-inch COT shelf to interface with sixteen PRL-770 4 LS RTs you can support as
many as 64 subscriber lines.
