Specifications

X723-300151 6-22 Issue 2
The self-test routine, which is automatically carried out after a cold start-
up, may be restarted by use of the Maintenance-self-Test command (6.2.5).
WARNING: The node will be isolated from the network during the period
of self test
PCM Faults
PCM loops may be applied to Dual LIUs in ports 1 and 2 by use of the
Maintenance - Data tests - Loops - menu (6.2.4). Both Local and Incoming
PCM loops may be set to each G.703 line signal. On completion of testing,
LIU loops if set to indefinite must be removed by use of the 'Reconfigure'
command. If an LIU is operated in an asynchronous system, frame slip
indications will occur.
Synchronisation Faults
Synchronisation faults are caused by failure of synchronisation sources.
For recovered clocks the failure conditions can be selected under the sync
configuration set up (5.4.3). Depending upon the option selected, failure
can be caused by PCM loss, service loss or receipt of an incoming frame
alarm. For the G.703 clock inputs failure occurs on signal loss. All clock
sources in the sync source selection list are also monitored for frequency
tolerance. If the frequency is outside the limits the source is classed as
failed.
Data Path Faults
Data signals through the multiplexer can be monitored by use of the
Maintenance - Data - Display sub-menu commands. The Data command
(6.2.3) periodically samples the data in the selected incoming timeslot. If
the data is not changing the data value is displayed as a hex code. If the
data is changing, or changes after display of a hex code, three asterisks
will be displayed. If the data subsequently settles to a constant value it
will again display the hex code. This will repeat until the Esc key is
operated.
A constant data code may be inserted into an outgoing timeslot by use of
the Maintenance - Set Data commands (6.2.2).
The Peak codes command is used for checking channels carrying VF
signals. This monitors the data in a selected incoming timeslot for a 5
second period. It then displays the maximum and minimum A-law values,
and approximate power levels. This repeats until the Esc key is operated.