Remote Digital
The Remote Digital Loop with 511/511E is
Loop with
shown below. After RDL is established the
511/511E
Remote units' Restart Timer is set to one
minute. This has been done because when the
511/511E generator is started on the local unit,
the Remote framer begins seeing unframed
packets. The Remote unit can not distinguish
the 511/511E pattern from the line being discon-
nected so the Restart Timer has been length-
ened to allow the pattern generator to function.
Once the 511/511E test is started, the Local unit
changes its' Restart Timer to one minute. The
pattern originates within the DSP and is sent to
the Remote unit. It is then looped back to the
Local unit where it is evaluated for errors. After
45 seconds, the Pattern Generator will timeout
and stops sending the pattern. The ER led will
begin blinking until the user turns off the
511/511E switch.
Figure 18. Block Remote Loop with 511/511E
31
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
32
Pattern
Gen/Det
Loop
Contr
ol
Loop
Contro
l
Pattern
Gen/Det
Processor
Processor
Framer
Framer
Line
Pattern
Gen/Det
Loop
Contr
ol
Loop
Contro
l
Pattern
Gen/Det
Processor
Processor
Framer
Framer
Line
