152-388-100-02, Issue 2Provisioning

 

Table 6.

HiGain Line Unit List 1 ADC Config Screen Options (Continued)

 

 

 

 

 

ADC Config Screen

Screen

 

Selection

Description

Options

Display Code

 

 

 

 

 

 

 

Remote Disconnect

RDA

 

ENA

Enables a remote DS1 LOS condition at the input to the H2TU-R to generate

Alarm

 

 

 

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 displays. The LOS is sent towards the network from the H2TU-C instead of AIS.

HDSL2 BER Threshold (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 CRC errors and counts display on the Monitor screen 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 Coding (DS1) 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.

H2TU-C 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 HiGain Line Unit 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 HiGain Line Unit 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 10-3BER required by most DLC systems.

H2TU-C-388 List 1

June 6, 2000

19