O3-4D1L3 U2
1631, Issue 4, October 2009
20
During a loopback, an alarm indication signal is sent to the DS1 Tip1/Ring1 (receive) pair.
However, if the unit receives (from the OC3 fiber link) an AIS signal in the DS1 circuit
being looped back, the O3-4D1L3 loopback will be deactivated to prevent the AIS from
being transmitted back into the OC3 fiber link. The deactivation helps isolate the fault that
caused the AIS.
If provisioned as an LT (CO-side) unit, the O3-4D1L3 automatically disables loopback
detection. Loopbacks can be enabled on any or all DS1s in a unit provisioned for NT via
the craft port loopback enable screen.
C. Manual Loopbacks
Three types of manual loopback are available for use via the craft port. These loopbacks
can be accessed via the Maintenance Manager sub-menu:
•
Network (toward optical interface)
•
Customer (toward DS1 interface)
•
Bilateral (toward optical and DS1 interfaces)
6. SPECIFICATIONS
Table 10 lists the electrical and physical characteristics of the unit.
Table 10. O3-4D1L3 Specifications
Description
Specification
A. System Characteristics
Loopback
Remote in-band/out-of-band DS1 loopbacks;
Local (manual) loopbacks
B. OC3 Interface
Optical Bit Rate
155.52 MHz, ± 20 ppm
Optical Wavelength
1310, 1550, 1471, 1491, 1511, 1531, 1551,
1571, 1591, and 1611 nm
Optical Input Level
See Table 1
Optical Link Loss Budget
See Table 1
Optical Receive Monitoring
Loss Of Signal, Loss Of Frame, Alarm
Indication Signal, Remote Defect Indication
FDA Laser Classification
Class 1
Optical Connectors
Duplex LC snap-in
