Chris, thanks for the rotary info.

I found it's not that important to know the exact specs for the rotary, as it turns out it's kinda easy for the cpu to tally counts from the rotary no matter how far off the timing is; as long as it's in a very broad ballpark. So I came up with some firmware code such that even hand clicking gives entirely reliable results. And I've been using a noise reduction algorithm with debounce and hysteresis that takes care of switching noise really well.

So with that R&D out of the way, I need to just finish up the "board bridging" feature, which lets one join two boards together so that 4 CO lines / 8 Extensions can be supported easily. Just adding a 40 pin ribbon cable to bridge the two boards, and changing some jumpers (still working on that last part) to get the line assignments to all line up across the two boards. This way all 5 lines on all 8 extensions can be active; lines 1-4 for CO, and line 5 for intercom. Lots of blinky lights!

So all that would be in "REV F".

Oh, and here's a pic of that nice 565 HKM rotary phone I acquired for testing. Great condition, and a nice smooth dial. The cord makes my whole office smell like hairspray though.. hoping that fully outgases over time, lol.

[Linked Image from seriss.com]

It's quite a beauty; it's been kept in perfect shape all these years. Many thanks to the ebay seller for such a nice phone.

Last edited by Greg Ercolano; 04/28/19 11:58 PM. Reason: small typo fix