31
32
Data Mode with
When the units enter DataMode it is possible to
511/511E Pattern
turn on the 511/511E pattern generators on both
Generators
ends of the link. Once a 511/511E pattern is
selected on one end of the link, the pattern gen-
erator will begin transmitting unframed 511/511E
through the line to the Remote end. A possible
problem with this test can occur due to the
Restart procedure. Once the Local 511/511E is
turned on, the Remote unit begins receiving an
unframed 511 pattern. If the Remote unit does
not turn on the 511/511E-pattern generator with-
in 4 seconds, the Remote unit will Restart and
enter the StartUp mode. Note that once the
511/511E-pattern generator is started the
Restart timer is changed to one minute (only on
the unit which has the pattern enabled). If both
units enable the 511/511E pattern within 4 sec-
onds of each other, both units will be transmit-
ting and receiving the 511/511E pattern. Both
framers are now receiving unframed data and
will restart after one minute. The 511/511E pat-
tern generators will TimeOut after 45 seconds
re-enabling the normal data path. The ER led
will begin flashing until the user terminates the
test.
Figure 19. Block Diagram DataMode with 511/511E
5.2.3 Using the V.52 (BER) Test Pattern Generator
To use the V.52 BER tests in conjunction with the Remote Digital
Loopback tests* (or with Local Line Loopback tests), follow these
instructions:
1.
Locate the “511/511E” toggle switch on the front panel of the
1094ARC and move it to the left. This activates the V.52 BER
test mode and transmits a “511” test pattern into the
loop. If
any errors are present, the local modem’s red “ER”
LED will
blink sporadically.
2. If the above test indicates no errors are present, move the
V.52 toggle switch to the right, activating the “511/E” test with
errors present. If the test is working properly, the local
modem's red “ER” LED will glow. A successful “511/E” test
will confirm that the link is in place, and that the Model
1094ARC’s built-in “511” generator and detector are working
properly.
Pattern
Gen/Det
Loop
Contr
ol
Loop
Contro
l
Pattern
Gen/Det
Processor
Processor
Framer
Framer
Line
*NOTE:
The above V.52 BER tests can be used independently
of the Remote Digital Loopback tests. This requires two opera-
tors: one to initiate and monitor the tests at the local Model
1094ARC, and one to do the same at the remote Model 1094ARC.
In this case, the test pattern sent by each Model 1094ARC will
not be looped back, but will be transmitted down the line to the
other Model 1094ARC.
