Verilink PRISM 3101 (34-00212) Product Manual - Manual (Page 23)

Configuration 3-7 PRISM 3101/3102
supports the following types of loops which are graphically
represented on pages 3-8 and 3-9.
Loop status changes can be made only when the
BERT function is not in the active mode.
NET PLB (Payload Loopback): The received network sig-
nal is looped back toward the network with signal regenera-
tion and framing and CRC regeneration. During the NET
PLB, data from the DTE is looped back to the DTE. The
NET PLB may be activated by receipt of out of band loop
code on the network receive signal or by selection in the user
interface maintenance screen.
FAR PLB: You can activate a NET PLB on the remote end
unit through this selection.
NET LLB (Line Loopback): The received network signal is
looped back toward the network with signal regeneration
only (framing and CRC intact). During the NET LLB, data
from the DTE is looped back to the DTE. The NET LLB
may be activated by receipt of inband or out of band loop
code on the network receive signal, by the front panel loop
switch, or by selection in the interface maintenance screen.
FAR LLB: You can activate a NET LLB on the remote end
unit through this selection or through the front panel TEST
switch (if configuration Switch S1-7 is set to Inband LLB).
NET MLB (Maintenance Loopback): The NET MLB com-
mand loops data at the T1 DTE port back toward the net-
work (passes network data to the DTE and returns data to
the network). The MLB affects only network channels
assigned to the T1 DTE.
DTE MLB: The T1 DTE MLB command loops all net-
work data back toward the DTE ports at the network inter-
face. Data is passed through to the network. Set the T1-
NET Timing to Internal when this loop is enabled.
DTE LLB: The T1 DTE LLB command loops data
received at the T1 DTE interface back toward the T1 DTE
(al DS0s are returned to the T1 DTE port). The T1 DTE
data is also passed to the network.
Port Loop: This field is used to loop high speed data port
from the network back to the network and data from the
DTE back to the DTE. The Port Loop may be activated by
receipt of inband V.54 fractional loop code or by this field.
On the PRISM 3102, each data port loops independently of
the other. The user activates a Port Loop on the remote end
unit through this field or by the front panel test switch. The
test switch can be used to activate a remote Port 1 loop if
configuration Switch S1 -7 is set to Inband V.54. Either
method causes the unit to transmit inband V.54 fractional
loop code toward the network in the port’s bandwidth.
Port Unloop: Pressing <return> takes down the specified
loop from the currently selected port.
BERT: This field selects the interface and direction for the
test pattern transmission. The choices are: T1 NET, T1 DTE,
One NET, One DTE, Channel 1-24, and IDLE. The 3102
includes the choices Two NET and Two DTE. The internal
BERT may also be activated through the front panel test
switch as specified under Hardware Testing on page 4 -1.
Pattern: Specifies the pattern to be transmitted during a
test. Modifying this field will not cause the pattern to be
transmitted (refer to Start Test). The choices are [QRSS],
[63], [511], [2047], [2
15
], [2
20
], [2
23
], [1:8], [3:24], [ALT],
and [CLEAR].
Test Length: Defines the run-time of test pattern genera-
tion and error accumulation. The choices are [15 min], [30
min], [60 min], [24 Hour], and [Continuous].
Start Test: Pressing <return> with the cursor on this field
starts the selected test pattern. TEST IN PROGRESS
appears once the test has started. To end the test, press
<return> on STOP TEST.
Reset Errors: Pressing <return> with the cursor on this
field causes the test error results to be cleared to zero.
The following fields are for display only. They reflect the
selected test parameters and the results of these tests only:
Pattern Sync: This field displays the current state of pat-
tern sync during a test. If no test is in progress, NO TEST is
displayed. If a test is active, but the receiver is not in pattern
sync, NO SYNC is displayed. If the receiver is in pattern
sync, IN SYNC is displayed.
Elapsed Time: Displays the amount of time elapsed since a
timed test began or, if completed, the total test time.
Bit Errors: Displays the total number of bit errors detected
since the test began or since error statistics were cleared (Up
to a maximum number of 999,999).
Errored Seconds: This field displays the number of asyn-
chronous errored seconds that have been detected since the
test began or since error statistics were last cleared. This
parameter includes bit error seconds and sync loss seconds.
% EFS: This ratio is derived from the number of error free
seconds divided by the number of seconds accumulated in
Elapsed Time.
L INE F AULT AND L OOP S TATUS
NET/ DTE Status: These two fields display the fault status
of the network and the far end DTE. They indicate current
fault conditions. They do not indicate that alarm thresholds
are exceeded. Status indications are described in NET/DTE
Status: These two fields display the fault status of the net-
work and the T1 DTE. They indicate current fault condi-
tions. They do not indicate that alarm thresholds are
exceeded. Status indications are described in Table 3-I.