ADC H2TU-C-202 User Manual page 30

Provisioning
SF Number
ESF-RAI to SF-RAI Overwrite (ROVR) Option. If the ESF-RAI to SF-RAI Overwrite (ROVR) option is
enabled, it allows a network ESF-RAI or ESF-RAI-CI pattern to be converted into a CPE SF-RAI or SF-RAI-CI
pattern, and overwrites bit 2 of every DS0 channel with a zero.
If the ROVR option is disabled, it prevents conversion of a network ESF payload with an embedded RAI pattern.
Disabling the ROVR option preserves the integrity of the CPE payload as it was originally transmitted.
Power Back Off (PBON and PBOC) Options. Power Back Off Network (PBON) and Power Back Off
Customer (PBOC) allow the HDSL2 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, preactivation sequence. It then compares
this level to the level it should be receiving according to the PBON and PBOC 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 PBON or PBOC
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.
AIS-CI (Alarm Indication Signal-Customer Installation). The H2TU-C, in conjunction with the H2TU-R,
supports the AIS-CI function. AIS-CI is a variant of AIS which is transmitted toward the network when either an
AIS defect or an LOS defect has been detected in the signal received from the CI at the H2TU-R unit. AIS-CI is
a regular AIS signal modulated by an AIS signature.
The AIS-CI signal is a repetitive pattern with a period of 1.26 seconds. The pattern is formed by sequentially
interleaving 1.11 seconds of an unframed all ones pattern and 0.15 seconds of all ones modified by the AIS-CI
signature. The AIS-CI signature is defined as a pattern which recurs at 386 bit intervals (two DS1 frame lengths)
in the DS1 signal and is 01111100 11111111 (right to left). This results in a repetitive pattern of 6176 bits. If the
first bit is numbered bit 0, bits 3088, 3474, and 5790 are logical zeroes and all other bits in the pattern are logical
ones.
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Table 10. SuperFrame Format
Terminal Framing Bit
1
2
3
4
5
6
7
8
9
10
11
12
June 28, 2002
Frame Bits
SuperFrame Signaling Bit
1
0
1
0
1
0
LTPH-UM-1161-01
0
0
1
1
1
0
H2TU-C-202 List 3F