Doing a rewire for the city of Phx,job requires "to present day code".Item requires ac power for smoke detecters.Its a 3 br home approx 1000 sq ft

Do you have an Electricians license to be doing this work?

Your building inspection department, the group that approves the work so you can get an occupancy permit, will tell you. The fire department should be able to advise as well. Does this help?

Please refer to the NEC edition of code that is being used in your area.

Basically, 1 inside each bedroom, outside the bedrooms and each floor and interconnected, so if one goes off they all go off(on?)
If wiring can't get units physically interconnected, you can use wireless interconnected detectors to connect all or in groups(if all detectors can't be connected with wires). Check local requirements.

... yes, you must check local requirements. Typically there is a city administrative code that also outlines some issues such as residential smoke detector requirements. In NJ the uniform construction code describes an installation similar to that described by Stratmando.
Contacting your local subcode official is the best route for success...

As I stated earlier, ask you building inspector or fire department. Local codes/ laws vary. In my city they require 10 year tamperproof units. Make sure you are installing what the powers that be want to see!

Please refer to the NEC edition of code that is being used in your area.This information is not in the NEC. It is in the building code.