sim cards for car kits/phones?

[Adams_16v]

How do car phones work?

I've got a sim card in my regular phone, but how would i get the same sim to work in a built in car kit/phone, rather than having to swap the sim everytime i got in the car?

just wondered as the car iv bought has a built in car kit/phone thats been professionaly fitted!

cheers

 

[BRUN]

buy a sim reader/writer off Ebay and copy your sim onto another

 

[Adams_16v]

i thought that, but does that clone your sim card so it will work in antoher phone?

and im guessing you cant have 2 phones on at the same time with 1 contract/number?