Specifications

Reference Guide
7-37
WAN Card WAN Card User Screens and Settings
LINE LB
The default setting for Line Loopback for the WAN HDSL card is
n/a
.
LOCAL LB
The Local Loopback setting allows you to loop the full T1/E1 line back toward the CPE.
Choosing
on
allows you to test the local system. Choosing
off
disables the loopback and
restores the normal signal path in both directions. If the WAN is in loopback due to a command
from a remote device, the loopback will be dropped if you choose
on
.
CH LB
The Channel Loopback setting allows you to loop the data in an individual DS0 time slot on
the WAN link toward the CPE (see Figure 7-25). However, you cannot use this feature to loop
multiple time slots or any portions of them. Refer to the user card chapters for other loopback
options that may allow you to loop part of a time slot or multiple time slots.
The loopback setting can be
off
or
clr
(clear). Clear means the entire 64 kbps clear-channel
time slot will be looped back, but without the Robbed-Bit Signaling data that may normally
be embedded in the time slot. If the WAN is in loopback due to a command from a remote
device, the loopback will be dropped if you choose
clr
.
LB ADDR
The Loopback Address setting, when used in conjunction with the Channel Loopback setting,
specifies which time slot will be looped back. Only one time slot may be looped back at a time
for each WAN T1/E1 link. The options for T1 lines are
1
to
24
. For E1 lines, the options are
1
to
31
.
LB GEN
The Loopback Generate setting generates out-of-band diagnostic codes that are sent to the
remote equipment. These codes are ANSI T1.403 compatible with T1 networks, and allow
you to command a latching loopback at remote DS1 equipment. The options are
off
,
llb
(Line
Loopback),
plb
(Payload Loopback), and
nlb
(Network Loopback). The
plb
setting is a
loopback of the entire signal except the framing bits.
Selecting
off
generates a loopback deactivate command corresponding to the last activation
command generated. e.g. if you send a
plb
command and then send an
off
command, the
off
command would be payload deactivate. Note that the actual transmission of the command
happens after you press “
s
” for
Save
. If you have already sent one of the loopback activation