I have a First Alert alarm system model FA110C. My question is how can I find the master code? I have tried the original 1234 code button, 1111 code button and the installer code 4112 code.
Any suggestions how to find the code?

There is a Process, but you also need the Installer/Program Manual to enter,view, and save data correctly. That same Manual will show the process.
Do you have the manual?
Can you tell more about the panel,(came with the house you just purchased? forgot after not using for a while?)

I had the alarm put in in 2003 and haven't been using it for the past 5 years. I want to set it up either to call my phone or contract with a alarm company. I need the master code either way to change the call out number. I have a programing guide but it doesn't give the master code. Either I forgot it or the installer never gave it to me so to keep him included for service reasons.

I will see if I can dig it up, To the point where you can program a new master code.
Alarm Panels can be confusing and bad data, no protection and false alarms can easily occur.