4-8
Diagnostics
GDC 048R154-000
Network QRSS Self Test
The Network QRSS Self Test function provides test pattern generation
and checking that involves the network interface while excluding the
DTE interface. The pattern it provides is a quasi-random signal
(QRSS).
The Network QRSS Self Test function appears three times in the
terminal interface Diagnostics Selection menu: once by itself and
twice in combination with loopback tests. The loopback-with-self test
functions are discussed on later pages under their own headings.
You can use the Network QRSS Self Test function by itself to perform
an End-to-End Self Test as illustrated in Figure 4-4. You can
command the test by means of either the terminal interface screen or
the front panel switches. Use of the terminal interface provides greater
detail in the test results. The test requires the cooperation of an
operator at the remote site to initiate the function in the remote DSU,
observe the results, and terminate the function.
In the Network End-to-End Self Test, two DSUs transmit internally
generated test patterns to each other for verification. Bipolar violations
are corrected during this test. Within each DSU, a Test Pattern
Generator creates the test pattern, and a Test Pattern checker
determines if the data it receives matches that which was transmitted.
The test checks both DSUs and the T1 link.
To initiate the test from the terminal interface Diagnostics Selection
screen, select
[2] Start Network QRSS Self Test
.
Figure 4-5 shows the switches and indicators that are involved when
you command a Network End-to-End Self Test from the front panel.
Remember that when you initiate the test from the front panel the only
display of results is the TM indicator flashing in response to detected
errors. The terminal interface Diagnostics Results screen does not
display the results of tests initiated from the front panel.
