Nortel Passport 15000 Hardware Description page 247

You must use Y-splitter cables that have been made according to the
following specifications, criteria, and considerations.
• Use the same specifications as listed in "Cable specifications for custom-
making LC cable assemblies" (page 244) except you can only use the
duplex single-mode (SM) type. At the FP end of the cables, you must use
small-form LC connectors. At the single end of the cable (the far end
from the FPs), the connectors are determined by whatever type of optical
interface you have for that port. Nortel Networks does not support
mixing single-mode and multimode at opposite ends of a connection. If
you must have MM at the far end:
— keep the total distance of the path less than 100 m (328 ft)
— use an appropriate attenuator on the receive (Rx) port (the
241-1501-240 Passport 15000, 20000 Hardware Installation,
Maintenance and Upgrade has the procedure for handling
attenuators)
• Use only the small-form pluggable (SFP) optical module with PEC
NTTP02CD, as described in "SFP modules for an NTHW44"
(page 240). Refer also to the figure "An example of a fiber optical duplex
Y-splitter cable assembly used for Y-protection" (page 249).
• The Y-splitter cable coupler must provide an equal split of the optical
signals, where each split signal meets or exceeds physical layer
requirements for intermediate reach (IR) under Telcordia GR253. The
legs of the cable after the split must be equal in length.
• The position of the coupler on each cable relative to all three ends of the
cable is critical for having effective cable management. Plan the length
of each installed cable especially between the port on the installed FP and
along the absolute cable path up to the nearest cable management bracket
so that its coupler:
— will not reside under an FP hood or anywhere across the front of the
shelf
— will not reside in a drawer of the fiber management unit (NTHW50)
— resides on the side of the NEBS 2000 frame or equivalent mounting
apparatus, or beyond, but not through or on any of the cable
management brackets
Chapter 4 Control and function processors 247
Passport 15000, 20000 Hardware Description 5.2S2