Remote Digital
The Remote Loop uses the EOC channel (an
Loop
out-of-band signaling channel) to establish the
remote link. Upon the RDL switch being thrown
or DTE initiation, a RDL_ON Request signal is
sent to the remote unit. The Remote unit then
responds with an RDL Acknowledge command
and the link is established. Data originates at
the local DTE and is looped at the Remote
PROCESSOR back to the Local DTE. Note that
the data is also passed through to the Remote
DTE and is not squelched. When a Remote unit
enters RDL, it changes its' Restart timeout to
one minute (the reason will be explain in the
RDL with 511/511E section). If the line is discon-
nected, the local unit will Restart (NS led activat-
ed) after 4 - 6 seconds, but the Remote unit will
wait for one minute before it Restarts. Note that
the transmit data at the Remote DTE is ignored.
When the switch is thrown or the DTE removes
the RDL request, the local unit will transmit an
RDL_OFF Request to the Remote unit. The
local unit will keep its' TM led active until this
request has been completely sent out. If the
switch is thrown again before the completion of
the termination phase the switch will be ignored
until it is placed back into the normal position.
25
26
Remote Digital
The Remote Digital Loop with 511/511E is
Loop with
shown above. 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 Processor 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.
Pattern
Gen/Det
Loop
Contr
ol
Loop
Contro
l
Pattern
Gen/Det
Processor
Processor
Framer
Framer
Line
Figure 16. Block Diagram Remote Loop
Figure 17. Block Remote Loop with 511/511E
Pattern
Gen/Det
Loop
Contr
ol
Loop
Contro
l
Pattern
Gen/Det
Processor
Processor
Framer
Framer
Line
