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4. TESTING
The DE-4 U-BR1TE responds to the B1, B2 and 2B+D
loopbacks as specified in TR-NWT-000397. This allows
an upstream network element, such as the ISDN switch,
U-BR1TE, or U-interface testers to initiate industry
standard EOC loopbacks. The faceplate can aid in
circuit turn-up and, in case of equipment malfunction,
sectionalize the network fault. For local test access, a
DS0 logic tester (equivalent to a TPI 108/109) can be
used along with the ten position Address Select Knob,
TEST pushbutton, and B1/B2 switches to perform local
and downstream loopbacks. See Figures 1 and 4 for
location identification. In addition, non-intrusive local
performance monitoring information is available through
the faceplate LEDs. The faceplate LEDs provide the U-
BR1TE operational and test status indications.
UBR1TE II
LPBK
AD6
AD
5
AD4
AD3
TEST
NORM
TST ERR
Rx
Tx
Figure 4. U-BR1TE II Faceplate
Loopbacks in the network-to-customer direction can be
initiated from the faceplate of the DE-4 U-BR1TE.
Faceplate initiated loopbacks are unobtrusive to unused
channels. Loopback on a single B channel will not
interrupt the other channels. The 2B+D loopback is
service affecting for the customer.
61410020L2-5C
1410020L2
CRTX
LPTX
NT1
AD1
AD2
B1
B2
PTRN
ACT
LP
CR
DS-0
LOGIC
C
Section 61410020L2-5, Issue 3
Faceplate indicators display the various conditions
occurring with respect to the DE-4 U-BR1TE. Table A
lists the faceplate indicators and their error messages.
The ten position rotary Address Select Knob (SW1)
determines which downstream network element is to be
looped. See Figure 1 for switch location and Table C for
setting descriptions.
Table C. Rotary Switch Options
DISPLAY
INTERPRETATION
AD1
Address #1, address of this unit
AD2
Address #2, the next downstream unit away
AD3
Address #3, the second unit downstream
AD4
Address #4, the third unit downstream
AD5
Address #5, the fourth unit downstream
AD6
Address #6, the fifth unit downstream
LPBK
Loopback, forces this unit to loopback either
B1/B2 from the front panel. Loopbacks occur
in both the customer and network directions.
CRTX
Carrier transmit, in the carrier direction
LPTX
Loop transmit, in the loop direction
NT1
NT1, address of the NT1
Selecting the B1/B2 DIP switch (SW5-1) sets the bearer
channel. The NORM/PTRN switch (SW5-2) selects
between normal and internal 2047 pattern generator
local test. The Test pushbutton (SW4) activates and
deactivates the test. See Figures 1 and 4 for switch
locations.
The following describes local test access testing for local
or remote loopbacks.
1. Connect the DS0 tester configured for Near Logic to
the Rx/Tx Bantam jack, and the clock cord to the
Timing Supply unit.
2. Using the ten position rotary Address Select Knob
(SW-3), select the desired address of the downstream
unit to be tested. See Table C for address information.
3. Select the appropriate bearer channel using the B1/
B2 DIP switch (SW5-1).
4. To activate the loopback test, press the TEST
pushbutton (SW4).
5. Upon completion of the test, select another address
using the ten position rotary switch, or another B
channel (SW5-1).
5
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