The 970-HA-JOKES Payphone Project
Contributors:
Nate
Nate 
MP3 Injection
In order to play our various easter eggs, we needed the ability to easily play MP3s, but more importantly we needed to hijack the handset. So a 2nd SPDT relay was added. This relay sits between the handset earpiece and the hook switch board. We can either connect the ear piece to the phone’s mainboard like a normal phone would be connected, or we can switch the relay and connect the MP3 output to the handset earpiece. This gives us man-in-the-middle control of what the user hears.