Physical Line Modules
Rear Panel
Equipment Overview
3-7
PN 76.8820IM30-A
Tellabs 8820 Multi-service Switch Router System Installation
Physical Line Modules
Physical line modules (PLMs) perform the Layer 1 functions, including optical-to-electrical
conversions, framing, mapping, and capturing of Layer 1 statistics. The control interface
between the line card processor and each PLM enables access by means of the craft
terminal for setting parameters, accessing internal registers, and other tasks typically
performed by craft personnel. A high-speed data bus transmits packets between each PLM
and the line card. The line card can detect the presence of a PLM and the type of PLM in
each of the four module interface positions.
The 8820 MSR PLMs are available in various configurations, as described in the section
Optical PLMs and Power Requirements, on page A-4
.
All PLMs are hot-swappable. Service is not disrupted when modules are removed or taken
out of service.
