Paradyne 3510 - Manual (Page 32)

COMSPHERE 3500 Series Data Service Units
3-10 March 1999 3510-A2-GN32-60
Digital Test (Multipoint)
Digital Test is a data disruptive test used to determine
if the control DSU, one selected tributary DSU, and the
multipoint network between these two DSUs are
functioning properly. This test requires a person at each
end, and the tester should be sure that no other tributary
will originate a transmission during the test, as this will
invalidate the test.
Multipoint Digital Test Overview
After the remote DSU is manually put in the Digital
Loopback, this test uses a test pattern generator built into
the local DSU. The generator sends a test message over
the network to a remote DSU where it is looped back
(Figure 3-5). The local DSU passes the received test
message to the comparator. The comparator checks the
message for errors. Isolated errors cause single flashes of
the local DSU front panel FAIL indicator. Steady errors
cause the FAIL indicator to flash at a six times per second
rate.
The DTE cable for each DSU is not required to be
connected to do this test. However, to do this test, each
DSU must be powered on, connected to the network, and
the network line must be functional.
The test requires an attendant at the tributary location
to press the DSU DL test switch. The person must be
contacted to establish the test starting time and duration.
To start the test, press the TP test switch at local DSU and
the DL test switch at the remote DSU. Look for FAIL
indicator flashes during the test. To end the test, press the
local DSU TP and the remote DSU DL test switches.
Figure 3-5. Digital Test (Multipoint) Diagram