Verilink 1558A (34-00228) Product Manual - Manual (Page 35)

1558A APS 4-12 LAPS Operation
A facility loopback loops the outgoing T1 signal back to the
1558A receive. The T1 signal level is regenerated and,
depending on the user option (regenerate CRC yes/no), the
CRC will or will not be regenerated. In addition to looping
the signal back to the 1558A receive, the signal is also trans-
mitted to the network (see the block diagram in Figure 4-2).
To unloop the unit, simply move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
CO Facility is displayed. Then depress the <return/enter>
key. The LAPS will issue a line unloop command. After a
few moments note that the NEAR status field changes from
Fac Lp to Soft Inhibit or Standby. Also note that the LP
indicator on the unit turns off. The CO Line loop is now off.
4.8.4 CO Equipment Loop
A DTE equipment loopback loops the incoming T1 signal
coming into the DTE (Tx) port back to the DTE port (Rx).
Only the T1 signal level is regenerated, not the CRC. In
addition to looping the signal back to the DTE port, the sig-
nal is also transmitted to the network.
To initiate a CO Equipment Loop, first target the path (A or
B) that you want to test by moving the cursor highlight to
the Target: field and then, using the spacebar, toggle the
field until it displays the side that you want to loop (Side A
or Side B). After you have selected either the A or B side as
the target for testing, move the cursor highlight to the Loop
field and toggle the field, using the space bar, until the field
displays CO Equipment. Then momentarily depress the
<return/enter> key. The LAPS will respond by sending the
following message to the user, “Warning! This loop dis-
rupts active service. Perform Loop? (Y/N).” If the user
enters y (yes), the system will initiate a DTE Equipment
loop. After a few moments, notice that the NEAR status
fields for both the A and B circuits has changed from Soft
Inhibit or Standby to Eq Lp. Also note that the 1558A front
panel DTE Loop LED indicator is on. If the user enters N
(no) when prompted with the warning message, the LAPS
system ignores the CO equipment loop command.
To unloop the unit, simply move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
CO Equipment is displayed. Then depress the <return/
enter> key. The LAPS will issue an Equipment unloop com-
mand. After a few moments note that the NEAR status field
changes from Eq Lp to Soft Inhibit or Standby. Also note
that the LP LED indicator on the 1558A turns off. The CO
Equipment loop is now off.
4.8.5 CPE Payload
A CPE Payload loopback is used to loop the far slave 1558A
unit from the master unit. At the far slave unit, the CPE Pay-
load loopback loops the incoming T1 signal (RX) coming
from the network (NET A or NET B) port back to the net-
work (TX, NET A or NET B). Both the signal and CRC are
regenerated. In addition to looping the signal back to the
network, the signal is also transmitted to the DTE port.
To initiate a CPE Payload loop, first target the path (A or B)
that you want to test by moving the cursor highlight to the
Target: field and then, using the spacebar, toggle the field
until it displays the side that you want to loop (Side A or
Side B). After you have selected either the A or B side as
the target for testing, move the cursor highlight to the Loop
field and toggle the field, using the space bar, until the field
displays CPE Payload. Then momentarily depress the
<return/enter> key. The LAPS will respond by sending the
appropriate loop command to the far slave unit. After a few
moments, notice that the FAR status field has changed from
Soft Inhibit or Standby to PL LP. Also note that the 1558A
far slave 1558A Loop LED indicator is on.
To unloop the unit, simply move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
CPE Payload is displayed. Then depress the <return/enter>
key. The LAPS will issue an unloop command. After a few
moments note that the FAR status field changes from PL LP
to Soft Inhibit or Standby. Also note that the Loop LED
indicator on the far slave 1558A turns off. The CPE Payload
loop is now off.
4.8.6 CPE Line
A CPE Line loopback is used to loop the far end slave
1558A unit from the master unit. At the far end slave unit,
the CPE Line loopback loops the incoming T1 signal (RX)
coming from the network (NET A or NET B) port back to
the network (TX, NET A or NET B). Only the signal is
regenerated by a CPE Line loop. In addition to looping the
signal back to the network, the signal is also transmitted to
the DTE port.
To initiate a CPE Line loop, first target the path (A or B)
that you want to test by moving the cursor highlight to the
Target: field and then, using the spacebar, toggle the field
until it displays the side that you want to loop (Side A or
Side B). After you have selected either the A or B side as
the target for testing, move the cursor highlight to the Loop
field and toggle the field, using the space bar, until the field
displays CPE Line. Then momentarily depress the <return/
enter> key. The LAPS will respond by sending the appropri-
ate loop command to the far end slave unit. After a few
moments, notice that the FAR status field has changed from
Soft Inhibit or Standby to Loop. Also note that the far slave
1558A Loop LED indicator is on.
To unloop the unit, simply move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
CPE Line is displayed. Then depress the <return/enter> key.
The LAPS will issue an unloop command. After a few
moments note that the FAR status field changes from Loop