AHB AOCR Failure Indication Unit - 1985

I cannot remember what was used as an indication panel before this but I expect it would have been a lamp and switch box with a lot of relays mounted somewhere in the Signal Box.

Our indication unit reduced all that into one little box and when the crossing was too far away for conventional 50V circuits we introduced a simple modem based transmission system.

The Circuit Diagram and my original track layout for the PCB.

The professional pen plots for the PCB.

The full Hardware design for the case.

The AHB AOCR Indicaion Unit Manual, written in Interword with the CAD designs produced in Technocad on our BBC B+ Computer.

The AOCR Indication and Transmission Units under test.

The Field End of a Transmission system and the Banavie Indication Unit.