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PLC Test Board

PLC Test Board
The PLC Test Board is designed to be conveniently placed into an empty slot in the 1-RU PLC Hybrid chassis, saving panel space and giving front and rear test access to carrier signals leaving and entering the panel. Its primary purpose is two-fold by providing testing functionality and replacing the carrier grounding knife switch that may be used in the panel.

PLC Test Board Diagram
The unit is electrically inserted between the panel’s final coax input/output going to the line tuner in the substation yard, as shown in the diagram to the right. If there are hybrids, then it is placed at the end of the hybrid chain going to the line tuner. It can be located inside the same chassis with the 1-RU PLC Hybrids if there is an empty slot. This does require a one-slot PLC Test Board front label overlay to be put on the slot it uses in the chassis.

For 1-RU PLC Hybrid chassis units that shipped before March 2023, please request the correct upgrade kit depending on the number of PLC Test Boards needed and whether the unit is a flush mount or projection mount type in order to retrofit an older chassis. This is because the front panel must be changed on the chassis to fit the larger hole required for the safety test switch

The intended application is to use one PLC Test Board per coax going out into the yard. See the table below for typical cases:

PLC Test Board Table


  • Compatible with 1-RU PLC Hybrid chassis
  • Easy replacement for coax grounding knife switch
  • Simple transmitter calibration with built-in 50 Ω load
  • Fast responding RF signal indicator
  • Convenient front panel test points/rear coax ports
  • Safety test switch opens and terminates coax
  • Bi-color LED indicates status of safety test switch position
  • Test functionality to allow insertion of meter while in service 
  • Jumper to provide 50 Ω termination for RX-only option 


Front of PLC Test Board


Rear of PLC Test Board