Question:
I have an Ademco 5706 wireless smoke detector (for an older alarm system) that was doused by a leaking ceiling. I am told that I must replace it with the exact same thing - in the next breath I am told that the part is obsolete and the only way is to upgrade the system (board and transmitters). The smoke detector is not in an easily accessible place to do a hardwire. Any suggestions if I could find a replacement or for any other options.

Answer: There are several brands of RF receivers which can be connected to a hard-wire circuit on an alarm panel. C&K Systems makes one. IIRC, ITI has a "Quick Bridge" which allows their receivers to work with most anyone's panel. You will need such an RF receiver and an RF Smoke Detector. Prices vary widely. Quality also varies widely. ITI and Linear are both well spoken of in this forum. Mr. Holger of HES can get you Linear. Mr. Brit Sandusky of ITI can point you to a nearby dealer of those products.