His taste in music is deplorable, but it's a good hack.
I was interested in what he did to hook up the keypad, since that was the hardest part of my payphone project. He says,
The most critical part of this hack is to intercept the keypad. Thankfully the phones use a conventional 8pin-keypad-style circuit, which makes this extremely easy :)
...and I'm like, huh? But he went from the keypad directly into Arduino GPIO pins, whereas I needed to go from there into a USB keyboard decoder board, which had a flat plastic ribbon cable connector on it instead of the spacious luxury of a molex connector with splicable wires. Sigh.
Anyway, I am also slightly disappointed in both his project and mine that in neither one does the original brass striker-arm telephone bell ring. He just plays an MP3. I really ought to fix that.