ADC H4TU-C-231-L5A User Manual page 25

LTPH-UM-1253-01
ADC Config
Menu Options
Remote Disconnect Alarm
(RDA)
H4TU-C Equalization (EQL) Option. The equalizer shapes the DS1 output signal of the H4TU-C to conform
to a very specific pulse template when it arrives at the DSX-1 cross-connect point. The degree of pulse-shaping
required is a function of the distance between the H4TU-C equipment bay and the DSX-1 panel. Thus, the
equalizer has six discrete settings, in increments of 133 feet to cause the maximized separation of 655 feet.
Alarm Pattern (ALMP) Option. To improve HiGain HDSL4 compatibility with the switch-to-protect features
used in Digital Loop Carrier (DLC) feeder applications, the H4TU-C has an Alarm Pattern (ALMP) option that
allows you to select either an AIS or LOS DS1 output payload for the following alarms:
•
LOSW on any loop
•
LOS DS1
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 HDSL4 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 HDSL4 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 H4TU-R, set the PBOC option
to its lower (ENH) level setting. Conversely, if the HDSL4 signal at the H4TU-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 HDSL4 loop to
momentarily drop and then reacquire synchronization. This setting can also affect the operating
margins.
Bipolar Violation Transparency (BPVT) Option. The H4TU-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 H4TU-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
H4TU-C-231 List 5A
Table 6. H4TU-C ADC Config Menu Options (Continued)
Selection Description
ENA Enables a remote DS1 LOS condition at the input to the H4TU-R to generate an LOS
alarm. AIS or LOS (depending on ALMP) is sent towards the network.
DIS Prevents a remote DS1 LOS condition at the input to the H4TU-R from causing an
LOS alarm. The front-panel Status LED still flashes red and the ALRM RLOS
message is displayed, but the alarm relay contacts do not close and LOS is sent
towards the network from the H4TU-C instead of AIS.
-3
BER required by most DLC systems.
October 15, 2003
-3 ). This maximum rate is more than adequate since it
Provisioning
17