152-319-100-02, Revision 02
Provisioning
H2TU-C-319 List 1 and List 1C
April 21, 2000
21
HDSL2 BER (HBER) Option.
The HBER option permits monitoring of loop integrity and reporting of alarms
when excessive errors are detected. The PM primitive used for this purpose is the CRC checksum performed on
the HDSL2 frame for both directions of transmission. It is, therefore, called a block error rate rather than the bit
error rate associated with the DS1 interface. The Monitor screen displays the CRC errors and counts for both the
H2TU-C and H2TU-R. The HBER option allows an alarm to be generated if the total number of CRCs at either
the H2TU-C or H2TU-R exceeds the selected BER threshold during the last 1-minute interval.
•
HBER option = 1E-6. Alarm is generated if CRC > 92
•
HBER option = 1E-7. Alarm is generated if CRC > 9
Once initiated, the HBER count clears when the CRC count drops below the selected threshold. Selecting NONE
inhibits this alarm.
DS1 Line Code Option.
The DS1 line code option should always be set to conform to the type of DS1 service
(AMI or B8ZS) being provided by the HiGain system. The Auto mode, which can adapt to either AMI or B8ZS,
should only be used in applications that require it (such as when HiGain acts as a standby circuit to DS1 circuits
whose line codes are not known or may be both AMI and B8ZS). This is because the Auto mode induces one BPV
in the DS1 bit stream whenever it switches from AMI to B8ZS. The Auto mode allows both the H2TU-C and the
H2TU-R to set its DS1 output code to that which is being received at the distant end DS1 input. This forces the
input and the output codes in each direction of transmission to be identical.
Equalization (EQL) Option.
Equalization is the configuration of system transmission characteristics within
specified limits. An adaptive equalizer inserts a frequency-shaped loss that corresponds to an equivalent addition
of an appropriate cable length. By simulating the additional cable loss necessary for correct operation, the
equalizer compensates for a range of variation in transmission path characteristics.
Bipolar Violation Transparency (BPVT) Option.
The H2TU-C-319 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-319
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
-3
). This maximum rate is more than adequate since it
exceeds the maximum 10
-3
BER required by most DLC systems.
Remote Disconnect
Alarm
RDA
ENA
Enables a remote DS1 LOS condition at the input to the H2TU-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 H2TU-R from causing
an LOS alarm. The front-panel Status LED still flashes red and the ALRM
RLOS message appears, but the alarm relay contacts do not close and LOS is
sent towards the network from the H2TU-C instead of AIS.
Table 6.
H2TU-C-319 List 1 and List 1C PairGain Config Screen Options (Cont.)
System Settings
Screen Options
Front-panel
Display
Code
Selection
Description
