Just some other 8-bit era hardware...

[tech58761]

Thought I'd share a project that grew out of some equipment I used to service; these were a few scrapped obsolete boards I squirreled away at some point.

It certainly took a while to draw and debug the schematics! That was easy compared to trying to figure out the firmware.

 

[Ruud]

And what is it / what does it?

 

[tech58761]

Part of a system where the power lines themselves can be used as a communications medium where a utility can control interruptible loads or read instrumentation remotely. The 'LMT' is a very early two-way endpoint (receive-only units were also produced and which are far simpler; some even resemble a normal US socket-type electricity meter), and the 'Repeater' is a device installed on long circuits to ensure the main communication unit in the substation can communicate with units at the end of the distribution circuit. The processor on both board sets appears to be a customized MC6801 with dedicated address / data pins instead of the ports otherwise available on the 6800 series ICs.

 

[Ruud]

Thank you for the info!