Specifications

Section 520-10S-WI3-203
030-101591 Rev. B
R
12
0806I3RB
47
41
13
7
5
15
55
49
Figure 12. Single Loopback Operation Diagram − Office Repeater Mode
DSX-1
520-10SWI3
(as Office Rptr)
Fiber Multiplexer
NET
(DSX)
AIS
CPE
(SPAN)
47
41
13
7
5
15
55
49
Figure 13. Dual Loopback Operation Diagram − Office Repeater Mode
DSX-1
520-10SWI3
(as Office Rptr)
Fiber Multiplexer
NET
(DSX)
CPE
(SPAN)
4.3.4.1 Loopback Timeout Option
See Paragraph 5.1.2 for loopback timeout enable/disable details.
5. LOOPBACK
The primary function of the 520-10SWI3 is loopback. The
520-10SWI3 supports both manual and remote loopback func-
tions and for both the Network side (single loopback) and the
CPE side (dual loopback). Single loopback allows for looping
the signal received from the Network on Side 1 (RCV From
NET) back to the Network on Side 2 (XMT To NET). The dual
loopback feature allows for looping the signal received from
the Customer on Side 2 (RCV From CPE) back to the Custom-
er on Side 1 (XMT To CPE). Signal regeneration is provided in
both the single and dual loopback transmission paths. Also,
while in the single loopback mode, the unit sends an AIS to-
ward the CPE. The following paragraphs describe the loopback
operations for each operating mode of the unit.
5.1 Manual Loopback - All Modes (Line Repeater,
Office Repeater, and NIU)
Manual (or local) activation of the loopback circuit is achieved
while on site by momentarily pressing the front-panel MLB
button for three seconds but less than five seconds.
- NOTE -
If the front-panel MLB button is pressed for longer than five seconds
but less than seven seconds, the unit enters the Dual Loopback mode
of operation. If the MLB button is pressed for longer than seven
seconds, the unit enters the Local Provisioning mode of operation.
When the MLB button is pressed and released within the 3 to
5-second time frame, the LPBK LED illuminates and a perma-
nent loopback (i.e., no timeout) is established. Manual
Loopback remains in effect until the MLB button is pressed a
second time or the loopback deactivate code is received.
5.1.1 Manual Dual Loopback
Manual activation for dual loopback is achieved while on site
by momentarily pressing the front-panel MLB button for
approximately five seconds but less than seven seconds.
- NOTE -
If the front-panel MLB button is pressed for less than the 5-second
time frame, the unit either returns to normal operation (if the unit is
already in the single loopback mode) or activates the single loopback
mode (if the unit is in the normal operating mode). If the MLB button
is pressed for longer than the 7-second time frame, the unit enters the
Local Provisioning mode.
5.1.2 Loopback Timeout Option
The 520-10SWI3 supports both single and dual loopback op-
eration. The unit also provides an automatic 120-minute
loopback timeout feature that can be either enabled or dis-
abled. To enable Loopback Timeout (LPBK T.O.):
LPBK While the LPBK TO LED is flashing, and if loopback
T.O. timeout is desired, simply press MLB button once. The
LPBK T.O. LED illuminates. The unit is now config-
ured and returns to normal operation.
If Loopback Timeout is not desired, simply let the