Will my old iPhone 4 still get a signal?

[The JTizzle]

If I keep my old iPhone 4 around as a emergency phone in the car with my old sim, and leave it off, will it still work down the road if I need to turn it on and make a call in a emergency as long as my new iPhone 4S is turned off?

 

[Roessnakhan]

You can probably still make emergency calls (911), but anything else would require you to swap the 4S SIM into the old 4. When you activated your 4S your 4 SIM was deactivated.

 

[The JTizzle]

how long does it take to deactivate the old sim?

 

[Roessnakhan]

I'm pretty sure if your 4S is getting a signal now then your 4's SIM should be kaput.