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Operating the DSU
4-113615-A2-GB20-20 December 1996
When a DBM (control or tributary) originates Remote
Digital Loopback, both the originating DBM and the
tar
geted DBM enter Test mode. No other test can be run at
the originating DSU or the tar
geted DSU until the Remote
Digital Loopback is aborted.
The DBM does not generate test results.
NOTE
To activate a V.54 Loopback from
the NMS to a DSU, first enable
V.54 Lpbk
(DSU option set) at
both the control and tributary
DSUs. Then, select
3600 remote-digital at the NMS,
not
V.54-remote-digital.
Bilateral Loopback
Bilateral Loopback (Bilat Lpbk) is a combination of
DTE and Digital Loopbacks operating simultaneously in
the same DSU. Both Bilateral and Digital Loopbacks are
selected from the DSUpt (DSU Port) or DBMpt
(DBM
Port) option set.
NOTE
If
Bilat Lpbk
is enabled,
requesting a Remote Digital
Loopback or Digital Test will
automatically initiate a DTE
Loopback, as well.
Digital Test
Only
available to a DBM, the Digital T
est (
DT
) checks
the functionality of a pair of DBMs. This test is run on the
DBM over the backup connection to a remote DBM for
point-to-point testing.
The remote DBM is placed in Digital Loopback, then
the local DBM transmits the 51
1-bit test pattern over the
network to the remote DBM for an operator-specified
length of time.
During the test, the TXD, RXD, and R
TS LED
indicators show the states of the leads at the DTE
interface if the DBM port leads are being displayed. At
the conclusion of the test, the local DSU releases the
remote DBM from Digital Loopback.
T
o review the results of the test, select
Displ (Display)
and press the
key to scroll through the results shown
in Table 4-3.
When the test is over
, the top line displays
Final
instead of
Active.
Table 4-3
Digital Test Results
Results Information Displayed
Time: Running test timer. (The Clr
selection resets the timer to
0:00:00.)
Tot Error: Running count of bits in error;
Max, if the maximum error
count has been reached, the
maximum being 64000. (The
Clr selection resets the counter
to 0.)
Err Secs: Running count of errored
seconds. (The Clr selection
resets the counter to 0.)
End-to-End Test
Only available to the DBM, the End-to-End (EE) Test
analyzes a control and a tributary DBM, and the network
circuit between them
in both dir
ections independently
. It
transmits fixed packets (or blocks) of data between the
DBMs When an End-to-End T
est is run, diagnostic data
may be disrupted.
T
o view the results of the test, select
Displ (Display)
and press the
key to scroll through the results shown
in Table 4-4.
When the test is over
, the top line displays
Final
instead of Active.