Patton electronic 1088/K User Manual
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the line or at the far end DTE interface is invalid. The remote unit
will remain in the StartUP mode, NS LED on, DSL Link LED stays
off, until the local unit is taken out of the Local Loop mode. After the
Local Loop is deselected, the units will both be in StartUP mode
and the link will be established.
A mode 2 Local Loop is shown in Figure 13. When the Local Loop
is initiated, either by the front panel switch or the DTE interface, two
separate loop paths will be started. In the first path, data presented
to the local DTE interface will be looped back to the local DTE
within the framer. In the second path, data presented at the far end
DTE will be transmitted to the local DTE and then looped back
within the local DTE Loop Control block with the Processor. After
the Local Loop is deselected, the units will be placed back into
DataMode and the normal data paths will be re-established.
Figure 14.
Block Diagram Local Loop Mode 1 with 511/511E
Figure 15.
Block Diagram Local Loop Mode 2 with 511/511E
Local Loop with 511/511E
When the unit is placed into a Mode 1. Local Loop and the 511/
511E pattern generator is activated, the local pattern generator
begins sending out a 511/511E pattern to the Loop Control block.
The Loop Control block will loop this data back to the 511/511E
pattern detector block, which will evaluate the data for errors.
Because the 511/511E pattern generator is contained within the
Processor the data is unframed so the framer will begin seeing
unframed packets. The framer receives this unframed data and
can not distinguish this information from a line disconnection (this
would cause the units' Restart procedure to start). What we have
done to allow this mode to work is to add time outs for the pattern
generators. When the 511/511E is initiated, the line restart proce-
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