Additional Features; Bipolar Violation Transparency (Bpvt) And Bit Error Rate (Ber) Options - ADC HiGain HRU-402 User Manual

150-402-100-03
A
DDITIONAL
The following describes additional information on some of the features
included with the HRU-402.
Bipolar Violation Transparency (BPVT) and Bit Error Rate
(BER) Options
The HRU-402 and its associated line units improve compatibility with Data
Link Control (DLC) feeder applications due to T1 BPVT transmit capability
between T1 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 T1 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 BPVTs in its T1 input. Standard HDSL systems correct input T1
BPVTs and thus prevent them from being detected by DLC terminals to
which they are connected. The HRU-402 and its associated line units remove
this limitation and become BPVT transparent by detecting and counting input
BPVTs at each end and then replicating them at the distant end T1 output port.
In addition, the CRC errors in each direction of every HDSL loop of each
span are also counted and added in with the BPVT count to produce a Total
Error Count (TEC). TEC indicates the integrity of both the T1 and HDSL
paths. A TEC in each direction is calculated every second by adding the
number of BPVTs to the number of HDSL CRC errors in that direction. The
maximum TEC count is 12000. This TEC number is converted into BPVTs
at the distant end during the following second at a rate of 1 BPVT every 128
T1 bits up to a maximum of 12000 (BER=7.7x10
more than adequate since it exceeds the maximum 10
DLC systems.
The BPVT transparency option is controlled by the BPVT user option, which
can be Enabled (ENA) or Disabled (DIS).
This BPVT is a "smart" option in that it is only available if the
HRU-402 is connected to an HLU-231 List 8x, HLU-319 List 5x,
or HLU-388 List 5x.
HRU-402 List 1 and List 3
F
EATURES
November 5, 1998
Appendix A: Specifications
-3
). This maximum rate is
-3
BER required by most
51