Section 150-232-100
Revision 01
Page 12
5.07 The following three user options can only be set using an ASCII terminal: CIRCUIT ID, DS0 BLOCKING and
MARGIN ALARM THRESHOLD.
5.08 The CIRCUIT ID option is set by selecting the “H” option from the terminal’s main menu shown in Figure 7.
The message “enter circuit ID # (24 characters max):” follows the “H” selection. Press ENTER after entering the
chosen set of alpha-numeric ID characters, then choose “C” to confirm.
Note: 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 screens as
shown in Figures 7 through 16. The ID does not appear on the HRU screens when the maintenance port is accessed
at the remote unit. Note that the Circuit ID is not set to its default (all blanks) setting when the DFLT setting option is
utilized.
5.09 To set the DS0 BLOCKING option, first select the SYSTEM SETTINGS (“C” option) from the main menu. The
menu shown in Figure 10 appears. Now press the letter “B” (shown in parenthesis) to select the DS0 blocking
function. The DS0 channels are blocked or unblocked by entering each channel’s number. Multiple channels can be
selected by inserting a single space between each entry. After all the new settings have been made press “E” for
“Enter”, then press “E” for Exit, then press “C” for Confirm. The new selections are now installed. If DS0 blocking is
invoked in a HiGain system that has an earlier version HRU that does not support the blocking option, blocking will
only occur at the DS1 output of the HLU. The HRU’s DS1 output will not be blocked. 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.
5.10 To set the MARGIN ALARM THRESHOLD select “G” from the SYSTEM SETTINGS menu. 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) drops below the selected threshold value. Since the margin can
never drop below 0, choosing “0” for the margin threshold disables the margin alarm function.
5.11 The HAIS option provides two choices for the DS1 transmit outputs at both the HLU and HRU for HDSL loss of
sync conditions. The “1LP” choice causes the AIS pattern to be transmitted at both DS1 outputs when either of the
two HDSL loops experience an out of sync (LOSW) condition or when a margin alarm occurs. This choice causes
the 12 channels on the surviving loop to be lost as all 24 channels are replaced by the AIS pattern. However it does
allow both downstream and upstream equipment to be made aware of the loss of one HDSL loop or a loop with low
margin. This 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 about 5 to
10 dB. Thus if the Margin alarm is set to 5 dB below the normal margin at turn-up, then when one conductor does
open, a margin alarm occurs and causes the AIS condition. This alerts 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. The 12 channels from the loop that is
lost are replaced by all ones.
5.12 All user options that affect the operation in both the HLU & HRU, such as HAIS, SAIS & DS0 blocking, will not
be available in older versions of the HRU that do not support these newer options.
5.13 The other system settings are set using an ASCII terminal in a similar manner. Simply enter the letter in
parenthesis of the parameter to be changed. Each entry of this letter scrolls the parameter to its next value. After all
selections have been made, enter “E” and then “C” to the resulting Confirm message. This activates the new
selections and returns control to the main menu.
