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MX2800 M13 Multiplexer User Manual Acceptance Test Procedure, Appendix A
61200290L1-1G A-7
DS1 to DS3 (Hard) Loopback
This test requires minimal test equipment, tests one DS1 at a time, and can be performed single-handedly.
It does not verify DS3 cabling integrity (transmit Vs. receive) to the DSX3 or connecting equipment.
Equipment Required:
• 1 DS1 test set capable of running a BERT test
• 1 DS3 DSX test cord
Follow these procedures to test one DS1 at a time:
1. At the DSX-3 cross-connect panel or connecting equipment, loop the DS3 from the MX2800 back on
itself. Confirm that the MX2800 sees a good DS3 signal. The
DS3 STATUS LED should be solid green
on the Active Controller, and the DS3 test set should be in frame synchronization with the MX2800.
2. At the DSX-1 cross-connect bay or connecting equipment, insert the
Transmit output of the DS1 test
set to the DS1
Input of the first channel of the MX2800. Connect the Receive input of the test set to
the
Output of the first DS1 channel of the MX2800.
3. Configure the DS1 test set for ESF/B8ZS and the desired BERT pattern, such as QRSS.
4. All alarms should clear on the MX2800, and the BERT should run error free. Troubleshoot as
necessary.
5. Repeat the above procedure for DS1 channels 2-28. The MX2800 will be in an alarm condition
because of the unterminated DS1 ports, but this condition should not prohibit a successful BERT.
6. Leave this test setup in place, as it will be used during the redundancy testing portion of this document.
Proceed to Verifying Alarm Notification.
5. VERIFYING ALARM NOTIFICATION
The MX2800 has two sets of alarm relay contacts available for connection to external alarm systems. They
are located on the back panel and are designated as
Critical, and Noncritical. Normally Open and
normally
Closed contacts are available for each of the relay outputs. The Critical alarm is activated when
the DS3 port experiences a Loss of Signal (LOS) event. The Noncritical alarm is activated when one of the
28 DS1 ports experiences a Loss of Signal event. Detailed alarm testing procedures are described below.
Critical Alarm Relay Test
This test actuates the Critical alarm relay contacts.
Equipment Required:
• 1 DS3 DSX test cord
Follow these procedures to test one the critical alarm relay.
1. Ensure that the DS3 is not in alarm. To do this, place a hard loopback of the DS3 toward the MX2800
using a test cord at the DSX-3 cross-connect panel or connecting equipment.
2. With the loopback in place, all alarms should clear on the Controller Module DS3 port. The
DS3
STATUS
LED should be solid green on the Active Controller).