Verilink 1558D (34-00255) Product Manual - Manual (Page 38)

LAPS Operation 4-12 1558D APS CSU/DSU
the target for testing, move the cursor highlight to the Loop
field and toggle the field, using the space bar, until the field
displays Far Payload. Then momentarily depress the
<enter> key. The LAPS will respond by sending the appro-
priate 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 1558D
far slave 1558D 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
Far Payload is displayed. Then depress the <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 1558D turns off. The Payload loop is now
off.
Far Line
A Far Line loopback is used to loop the far end slave 1558D
unit from the master unit. At the far end slave unit, the Far
Line 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). Only the signal is regener-
ated by a Far Line loop. In addition to looping the signal
back to the network, the signal is also transmitted to the
DTE port.
To initiate a Far Line loop, first target the path (A or B) that
you want to test by moving the cursor highlight to the Tar-
get: 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
Far Line. Then momentarily depress the <enter> key. The
LAPS will respond by sending the appropriate loop com-
mand 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 1558D 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
Far Line is displayed. Then depress the <enter> key. The
LAPS will issue an unloop command. After a few moments
note that the FAR status field changes from Loop back to
Soft Inhibit or StandBy. Also note that the Loop LED indi-
cator on the far slave 1558D turns off. The Line loop is now
off.
CSU Loop
The 1558D, when configured as a Slave unit with the CSU
mode Enabled, will respond to industry standard CSU loop
and unloop commands. A CSU loopback loops the incoming
T1 signal (RX) coming from the network (NET A or NET
B) back to the network (TX). Only the signal is regenerated
by a CSU loop. In addition to looping the signal back to the
network, the signal is also transmitted to the DTE port.
To initiate a CSU 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
CSU. Then momentarily depress the <enter> key. The LAPS
will respond by sending the appropriate loop command to
the far end slave unit. After several seconds, notice that the
FAR status field has changed from Soft Inhibit or StandBy
to Loop. Also note that the far end slave 1558D front panel
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
CSU is displayed. Then depress the <enter> key. The LAPS
will issue an unloop command. After several seconds, note
that the FAR status field changes from Loop to Soft Inhibit
or StandBy. Also note that the Loop LED indicator on the
far slave 1558D turns off. The CSU loop is now off.
NET Loop
The NET loop command is used to generate 5-bit patterns
towards the far end equipment. These patterns may be used
to loop a network interface device or a CSU. To initiate a 5-
bit NET pattern, 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 NET. Note
that when the NET command is selected, a user definable 5-
bit code field is also displayed [10000]. This 5-bit field can
be set to any combination of ones and zeros by moving the
cursor highlight to this field and then entering the desired
combination of ones and zeros at the message prompt.
The most common network interface loop up 5-bit pattern is
[11000]. The most common unloop 5-bit pattern for network
interface devices is [11100]. After selecting the 5-bit pat-
tern, move the cursor back to the Loop field and press the
<enter> key. The LAPS responds by sending the selected
NET 5-bit code to the far end equipment for 5 seconds or
more.
To unloop the network interface device, simply move the
cursor to the Unloop field and toggle it with the spacebar,
until NET is displayed. Note that when the NET command
is selected, a user definable 5-bit code is displayed [11100].
This field may be set to any combination of ones and zeros
by entering the desired combination. The most common net-
work interface unloop command is [11100]. After pressing
<enter>, the LAPS will issue a NET unloop command for 5