365-575-102 Detailed Level Procedure: DLP-512
Issue 8.0, July 2002 Page 1 of 14
Install/Remove Lightguide Buildout
Description
This procedure is used to select the proper value of Line Build Out (LBO) to be
used on the circuit pack’s faceplate jacks. High Speed links may require an
attenuating LBO on the RCVR (IN) jack, and a zero-dB (0dB) LBO on the
TRMTR (OUT) jack. As a contrast, Low-Speed links may require an attenuat-
ing LBO on the TRMTR (OUT) jack, and a zero-dB (0dB) LBO on the RCVR
(IN) jack. In rare instances LBOs can be placed in the LGX, but this is NOT
recommended. Typically, although there is not any requirement, the span
fibers will connect to an LGX. And, “Fiber Jumpers” are used to connect the
LGX’s span fibers to the circuit pack faceplate LBOs.
This procedure covers the selection of both single-mode (SM) and multi-mode
(MM) LBOs, span fibers, and associated fiber jumpers. In order to determine
the correct type of connection devices (SM or MM) you will need to know the
type of circuit pack being used and its application. The information contained
within Table A should help in this selection.
Table A – (Some) Optical Link Configurations and Span Component Requirements
Type of
Circuit Pack
Circuit Pack
Transmitter
Device
Type
LBO
Span Fiber Jumper Type RCVR
Circuit Pack
RCVR
Device
OC-48 Laser (SM) SM SM SM OC-48 Diode (MM)
OC-12 (T939A)
*
* T939A circuit packs are shipped from the factory with 0dB LBOs on both the IN and
OUT jacks.
Laser (MLM) SM SM SM
OC-12
†
† If the attenuation LBO is installed at the transmit (OUT) jack–then normally only a
0dB LBO is required at the receive (IN) jack. If an attenuation LBO must be used at
the input (IN) jack on the LAA10B or T939A, then a MM LBO must be used.
Diode (MM)
OC-3 (LAA10B)
‡
‡ LAA10B circuit packs are shipped from the factory with a 0dB LBO on the IN jack and
a 7.1dB SM LBO on the OUT jack. LAA10B replaces LAA10 circuit packs, which are
rated DA.
Laser (MLM) SM SM SM OC-3* Diode (MM)
OC-3 Laser (MLM) MM MM MM IS-3* Diode (MM)
OC-3 Laser (MLM)
SM
§
§ This option uses more expensive components than the previous (above) option.
SM SM IS-3* Diode (MM)
IS-3 (LAA5)
¶
¶ LAA5 circuit packs are shipped from the factory with 0dB LBOs on both the IN and
OUT jacks.
LED (MM) MM MM MM OC-3* Diode (MM)
IS-3 LED (MM) MM MM MM IS-3* Diode (MM)
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