Section 150-431-114
Release 01
Page 7
5.07
The Circuit ID option is set by choosing the
H option from the terminal Main Menu screen
(see Figure 7 for non-doubler applications and Figure 16
for doubler applications). The message “ENTER
CIRCUIT ID#:” (24 characters max) follows the “H”
selection. Press Enter after entering the chosen set of
alpha-numeric ID characters; choose C to confirm. Note
that if more than 24 characters are entered, a “Beep” is
emitted, and only the first 24 characters are accepted. The
ID appears in all HLU-431, List 1D screens, as shown in
Figures 7 through 14 for non-doubler applications and
Figures 16 through 34 for doubler applications. The ID
does not appear on the HRU-412 screens when the
maintenance port is accessed at the remote unit. Note that
the Circuit ID can not be set to its factory setting (all
blanks) setting when the DFLT setting option is utilized
(see Section A Paragraph 5.03).
5.08
To set the DS0 Blocking option, from the Main
Menu screen, press C to select the System
Settings Menu screen. The menu shown in Figure 10 (for
non-doubler applications) and Figure 22 (for doubler
applications) appears. Press B, as shown in parentheses of
the DS0 blocking selection. The DS0 channels are
blocked or unblocked by entering each channel number.
Multiple channels can be selected by inserting a space
between each entry. After all the new settings have been
made, press E (“Exit”) and C (“Confirm”). The new
choices are now installed. Also, all blocked channels are
temporarily “unblocked” for all HiGain system loopback
tests. This allows the standard full bandwidth T1 loopback
tests to be performed.
5.09
To set the Margin Alarm Threshold, select G
from the System Settings Menu screen. Enter the
desired minimum acceptable alarm threshold from the 0 to
15 dB range. This causes a minor alarm to occur if either
the margin on HDSL loop 1 (MAL1) or loop 2 (MAL2) of
any span drops below the selected threshold value (see
Section 4). Since the margin can never drop below 0,
choosing 0 for the margin threshold turns the margin alarm
off.
5.10
Other system settings are set by using a terminal
in a similar manner. Enter the key represented
by the letter in parentheses of the parameter to be changed.
Each entry of this letter scrolls the parameter to its next
value. Hit the Enter key after making each selection.
After all selections have been made, press E to “Exit” and
C to “Confirm” the changes. This activates the new
choices and returns control to the Main Menu screen.
5.11
The new T1 transceiver chip in the List 2D allows
the unit to process both B8ZS and AMI code
inputs, regardless of the DS1 code setting (AMI or B8ZS).
Earlier units caused input BPV, if B8ZS patterns were
processed while in the AMI mode. When the newer units
are in the AMI mode, they can receive B8ZS but can only
transmit AMI. For this reason, mixed systems (those
consisting of both HLU-431, List 1D and older Lists 1, 2,
3, 3A and 4 HRU-412 units) will respond differently in
each direction for B8ZS inputs when in their AMI modes.
5.12
The Self-test mode, which occurs when both
HDSL loops are not in-sync, has been enhanced
to include the input DS1 transceiver chip in the self-test
procedure. This process can cause the Alarm Indicating
Signal (AIS) pattern, which is normally transmitted from
the HLU-431, List 1D during these out-of-sync intervals,
to exhibit occasional BPVs.
5.13
The HAIS option provides two selections (1LP
and 2LP) for the T1 transmit outputs at both the
HLU-431, List 1D and HRU-412 for HDSL loss-of-sync
conditions. The “1LP” selection causes the AIS pattern to
be transmitted at both T1 outputs when either of the two
HDSL loops experience a loss-of-sync (LOSW) condition
or when a margin alarm occurs. This choice causes the 12
channels on the surviving loop to be lost as they are
replaced by the AIS pattern. However, it allows both
down and upstream equipment to be made aware of the
loss of one HDSL loop or a loop with low margin. The
1LP selection is the preferred setting to be able to initiate
an AIS state with just one conductor open in either of the
HDSL pairs. Short loops, below about 16 dB of loss at
200 kHz, can remain in-sync with one conductor open.
Since the loop is still in-sync, no LOSW condition occurs.
However, the margin on a one-conductor loop drops from
5 to 10 dB. Thus, if the margin alarm is set to 5 dB below
the normal margin at turn-up, when one conductor opens, a
minor alarm occurs and causes the AIS condition. This
alerts the maintenance personnel of the problem. The
“2LP” choice requires both HDSL loops to be out-of-sync
(LOSW) before the AIS signal is transmitted. This choice
preserves the integrity of the 12 surviving channels when
just one loop is lost.
5.14
All user options that affect the operation in both
the HLU-431, List 1D and HRU-412, (such as
HAIS, SAIS and DS0 blocking) are not available in older
versions of the HRU-412, Lists 1, 2, 3, 3A, and 4 that do
not support these newer options.
