1) Bernard............if the receptacle is indeed a GFCI type and your smokes are wired to the LOAD side of the GFCI, it is never recommended to have smokes wired to a GFCI due to nuisance tripping and also for safety purposes.
2) A GFCI has 2 wiring connections located on the back of the receptacle, ie, LINE side and LOAD side. If the smokes are wired to the LOAD side screw terminals and the GFCI has been tripped, the smoke alarms will never work on AC voltage and would only work if they are a combo AC/Battery type.
3) Hard-wired smokes typically have 3 wires, ie...... 1 hot, 1 neutral and 1 inter-communicated. The inter-communicated wire is wired to other smokes within the house in a daisy chain fashion. If 1 smoke is triggered, it will send a voltage signal to the remaining smokes and all of them will sound simultaneously. It is very possible that if the smokes are connected to a GFCI LOAD side, the smokes were wired incorrectly and possibly the "inter-communicated" wire was connected to the LOAD side of the GFCI. If you feel comfortable in doing so, you would need to perform a visual inspection as to how things are wired to determine and confirm if this is what is causing the problem. If not comfortable working with electricity or you don't have the proper voltage testing instruments, I would recommend having a licensed electrician check things out.
4) The other outlet in the other room may also be wired as a downstream receptacle off of the same GFCI receptacle on the LOAD side and causing the same problem.
5) I would recommend to remove any smokes wiring in the house and get them off of the LOAD side of any GFCI breakers or GFCI receptacles. They should be re-wired and not on a GFCI device.
Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.
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