Section 150-431-114
Release 01
Page 6
5. SYSTEM OPTIONS
5.01
The HLU-431, List 1D contains a non-volatile
RAM (NVRAM) which stores the system options
settings. No dip-switches or jumpers are required to
configure these system options. They are set via push
buttons on the front panel or through the RS-232 interface
or from the Maintenance Terminal interface. The System
Settings are retained if shelf power is lost or if the HLU-
431, List 1D is unplugged. Table 1 lists the HLU-431,
List 1D System Options. Figure 10 and Figure 22
illustrate the same options on the HLU-431, List 1D non-
doubler and doubler System Settings Menu screens,
respectively. In the System Settings Menu (which is
identical for both non-doubler and doubler applications),
the settings shown represent the factory default settings.
5.02
The Setup momentary push buttons (Mode and
SEL) are used to set the options from the HLU-
431, List 1D front panel. To initiate the Options Setting
mode, press the Mode button, for at least one second, but
less than three seconds, and release. The message
displayed on the front panel alternates between the first
system parameter and its current setting. Pressing the SEL
button scrolls the display (one at a time) through all
possible settings of the parameter being displayed. After
the desired setting has been selected, press the Mode
button. This updates the currently displayed mode to the
selected setting, then selects the next configurable
parameter. After the last parameter has been selected, the
display shows “CONF NO (Confirm? (Yes/No)).” If the
Mode button is pressed at this time, none of the changed
parameters are installed. If the SEL button is pressed, a
“YES” message is displayed, and the selected changes are
installed. In either case, the display returns to its normal
mode. The display also returns to its normal mode,
without installing any new changes, if, after 30 seconds,
neither button is pressed.
5.03
All 14 user options can be set to the factory
default values by pressing the SEL button for six
seconds until the message “DFLT NO” appears. To set the
default values, press the SEL button while the “DFLT
NO” message is displayed. “DFLT YES” will be
displayed, indicating the factory default values are now in
effect. To terminate the Default mode, without setting the
factory default values, press the Mode button or do
nothing for 30 seconds. The latter returns the display to its
normal state.
5.04
Pressing the Mode button for three or more
seconds causes the display to scroll through the
HLU-431, List 1D software version number, its list
number, the type of frame pattern being received from the
DSX-1, the line code setting of the HLU-431, List 1D, and
all 14 options settings. The line code parameter is the
actual DS1 line code being received by the HLU-431, List
1D when the DS1 code pattern is set to Auto. Otherwise,
the line code parameter mimics either of the other two line
code settings, AMI or B8ZS, and is not determined by the
received line code.
5.05
The DS1 line code option should always be set to
conform to the type of T1 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 T1 circuits whose line codes are
not known or may be both AMI and B8ZS), because it has
the following two limitations:
1. The Auto mode induces one BPV in the T1 bit
stream whenever it switches from AMI to
B8ZS.
2. The Auto mode allows each HiGain end (HLU
and HRU) to set its DS1 mode to the code it is
receiving at its local T1 input port. This
makes each unit’s code independent of the T1
code, which is sent from the distant T1 input
port. Thus, if the line codes being received by
HiGain are different in each of the two T1
directions, the HiGain T1 output codes will
not match their respective T1 input codes at
the other end. This could cause the customer’s
received data to be AMI instead of B8ZS, and
thus violate the one’s density rules by having
excessive zeroes.
5.06
The following three user options can only be set
via the RS-232 terminal interface: Circuit ID,
DS0 Blocking, and Margin Alarm Threshold.
