I am really glad I found this discussion, it helped tremendously on trying to figure out how to program my Ernest ETX. some notes from my experience: I could not find a 16x2 LCD on Ebay with just 14 pins. Most 16x2 LCD displays now have 16 pins. The extra 2 pins are for powering the LED back lighting. Pin 15 is 5VDC + and pin 16 is 5VDC -. This point is almost useless in my case as the PCB on the phone did not supply enough power to drive both the LCD and LED back light at the same time. I could not get anything to function properly until I disconnected the power (pin 15 and 16) to the LED back light. As far as wiring the contrast (terminal 3 on LCD) I tried using a jumper wire from pin 2 (5VDC +) to pin 3 (contrast) and I was never able to distinguish anything appearing on the LCD. I also tried it with the wire disconnected and with it just wired to the IDE connection on the phone PCB, no luck. I then tried wiring a 10k Pot with one side to pin 2 5VDC+, the other side to pin 1 (5VDC-) and the center terminal to pin 3 (contrast). At this point I could adjust the contrast to clearly read the LCD display. The pins on the 16x2 LCD were clearly marked but I was unsure of the pin configuration on the phones PCB where the LCD plugs in. This is the pin orientation of the socket on the phone PCB that I found: This is as you look at it on the phones PCB board with the phone standing up in regular position. Top 14- 13 12- 11 10- 9 8 - 7 <This is where the indexing notch is 6 - 5 4 - 3 2 - 1 bottom I am now able to access the programming menu on the LCD I hope this helps anyone looking for it. When I started this project I was told I could not run the pay phone off a voip system. That is not true, I am currently running this from an Ooma voip box. I had to connect a GE wireless phone jack system with the master connected to the Ooma Telo, and the slave unit connected to the Pay Phone. It seems the GE wireless phone jack system reproduces the old landline voltages much more accurately than the Ooma Telo Voip box. If anyone has any experience in programming the Ernest ETX I would appreciate some guidance. I would like to program the phone so all calls are free (it will be mounted inside my home). It would be even better if I could program it so the caller had to place a quarter in the phone but it was returned when the handset was replaced and call ended. I have been through the programming features and have not figured out how to achieve this.