ADC HiGain H2TU-C-202 User Manual page 26

Provisioning
Power Back Off Customer (PBOC) and Power Back Off Network (PBON) Options. Power Back Off
Customer (PBOC) and Power Back Off Network (PBON) allow the HDSL circuit to support two transmit power
templates: default (DEF/higher level) and enhanced (ENH/lower level). These are defined in Section 6.1.4.2 of
the ANSI T1E1.4 HDSL2 standard. Each HDSL2 receiver detects the level it is receiving during the start-up,
pre-activation sequence. It then compares this level to the level it should be receiving according to the PBOC and
PBON option settings (DEF or ENH). If the received level is outside the template limits, the receiver sends a
message to the upstream HDSL2 transmitter requesting the proper level. These levels are adjusted only during the
start-up routine or if the PBOC or PBON option settings are changed during normal operation. Since the ENH
template levels are up to 15 dBm below those of the DEF template, the ENH setting can be used to reduce crosstalk
levels into adjacent circuits. (For example, if crosstalk noise is being induced by the H2TU-R, set the PBOC option
to its lower (ENH) level setting. Conversely, if the HDSL2 signal at the H2TU-R is being affected by crosstalk
noise induced from adjacent pairs, set the PBOC option to its higher (DEF) level setting.
Changing these Power Back Off option settings on a live circuit causes the HDSL2 loop to
momentarily drop and then reacquire synchronization. This setting can also affect the operating
margins.
Bipolar Violation Transparency (BPVT) Option. The H2TU-C improves compatibility with Digital Loop
Carrier (DLC) feeder applications because of its ability to transmit DS1 BPV occurrences between its DS1
interfaces. This feature is required to support protection switching in DLC applications. Each DLC terminal must
be able to monitor the integrity of its Receive DS1 payload and then switch to the protect line when the integrity
of the path drops below specific user selected limits. An essential requirement of this feature is the need for each
DLC terminal to detect BPVs in its DS1 input. Standard HDSL systems correct DS1 BPVs at the input and,
therefore, prevent them from being detected by the DLC terminals to which they are connected. The H2TU-C and
its associated remote units remove this limitation and become BPV transparent by detecting and counting input
BPVs at each end and then by replicating them at the DS1 output port of the distant end.
The BPV count is converted into BPVs at the distant end during the following second at a rate of 1 BPV every
128 DS1 bits up to a maximum of 12000 (BER = 7.7 x 10
exceeds the maximum 10
DS1 BER (DBER) Option. The DS1 BER alarm occurs when any of the DS1 or DSX-1 performance
monitoring parameters listed in
through 11:59:59 PM. These thresholds correspond to a 10
or when Master Clear is selected.
18
-3
BER required by most DLC systems.
Table 8 exceed the counts shown for the 24-hour period between 12:00:00 AM
Table 8. DS1 and DSX-1 24-Hour PM Threshold
Parameter
CV-L (BPV)
ES-L, ES-P, PRM, PDVS-L
SES-L, SES-P
UAS-P, UAS-L
June 6, 2003
-3
). This maximum rate is more than adequate since it
-6
BER. All PM counters clear to zero at 12:00:00 AM
Threshold Count
133,400
648
100
10
LTPH-UM-1208-01
H2TU-C-202 List 7G