Hi ab, a conventional fire alarm will use diode bases on the detectors with a EOL resistor or capacitor on the final detector unless its an addressable system, I guess from your question you will not know how to test the system after re-connecting it so it would be best IMO to get a qualified person in to check and test the system for you as they will know what parts are required and be compatable to the system.
Afterall it is a safety sytem to protect life and not to be touched by un-trained people for that reason, not the answer you were after i know but hope that helps.