Initializing the Maintenance Terminal Screens
150-402-111-02
44
December 8, 1998
HRU-402 List 1A
SmartJack Set to ENA
Upon detection of a valid SmartJack Loopback command, a loopback is
activated and the T1framer chip transmits the AIS pattern to the NI and also
back to the HRU-402 T1 receiver circuit. In addition, the customer’s T1 XMT
input is disconnected and terminated. The AIS pattern is examined by the
HRU for its overall integrity. This pre-loop test lasts for about 300 ms and
terminates in one of the following two conditions:
•
Pre-loop Failed- If the transmit and receive all 1s patterns do not match,
a problem in the HRU is indicated and HiGain declares an HRU
PRE-LOOPBACK FAIL condition. This terminates the loopback test
and returns the HRU to its unlooped normal state. This indicates a
defective HRU.
•
Pre-loop Passed - If the transmit and receive patterns match, the system
declares an HRU Pre-loop Passed condition. All active circuits are
working. The loopback remains active. This puts the HiGain system in
its AIS/ENA SmartJack loopback state. It remains in this state until a
loopdown command is detected or the default time out period (if
enabled) expires.
When the HRU is in its AIS/ENA SmartJack Loopback state, its T1 input
LOS, Code and Frame monitoring circuits are connected to the unframed all
ones pattern which is being looped back to these circuits through the T1
Interface chip. The CPE input signal is no longer being monitored since its
input circuit has been opened and terminated. This forces the FRM LEDs off,
the Local (LOC) Loss of Signal (LOS) LED off and the Code LEDs to
indicate AMI if the HLU Code option is set to either AUTO or AMI. The
code LEDs indicates B8ZS if the Code option is set to B8ZS.
SAIS Set to DIS
This SMJK Loopback state is initiated in the same manner as when the ENA
option is chosen. However, once initiated, the AIS is not sent to the CPE.
Instead the network signal is sent both towards the NI and through the
loopback towards the network. As before, the customer’s T1 transmit input
port is opened and terminated. This loopback state remains until a loopdown
command is issued or the default timer (if enabled) expires.
