Payphone
Some time ago, I purchaced a refurbished payphone online. I bought it unprogrammed, as I wasn't sure how I wanted to set it up, but had some issues getting it to keep some of my settings. I had plugged the internal battery in, and had followed all the instructions. Yet my changes to change collection never seemed to last. Well, recently I also discovered that the phone wasn't working at all. I opened the phone and removed the battery and tested it, and it was dead. So I thought I'd take the board out and see if I could bypass it coin collection completely, and I discovered a second battery on the back of the board. So I did a little more digging, and discovered the first battery apparently provided power to the relay, and the one I discovered powers the chip which saves the setting. I tested it, and the voltage measured a bit low as well. Replacement batteries ordered, so I should finally be able to set the phone the way I'd like it set.
In the process, I also discovered a blog post about fixing a Protel payphone. It appears to be more-or-less the same phone as I have, and has a lot of interesting information that I hadn't run across before. Worth checking out if you're interested in such things at all.
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