Help identifying payphone model and missing internals

[qcstewart]

Hello!

My Grandfather ran a payphone business in North Florida from the 90s to early 2000s. I have one of his old payphones that was left after he passed away and would like to get it back to working (or to where it would work with a SIP ATA). I think it is something like a Protel 7000. From what I can tell it is missing the control board, but it does provide dial tone when connected to the ATA so I think the handset is working. If anyone could help me in identifying the model and even what is missing from inside to get back to a working state that would be greatly appreciated!

Thank you, have a good day,