Are all sim cards compatible with ALLPHONES
Most carriers lock their handsets, preventing SIM card exchange among any device. These handsets can be unlocked and unbound from a carrier if the user has the right code. The exact process to do this varies by phone manufacturer and phone model.
Not all SIM cards are compatible with all phones, though some of them fit into each other. There are certain phones with SIM locks, which cannot accept just any SIM card to be inserted in them.
Yeah most of the time
Not all sim cards are the same, iPhone for example use small sim cards and you need adapter like this:http://www.coolcasing.com/2in1-sim-card-adapter-iphone-CC-IP5G-8005
No, absolutely not. Devices function on different carriers, different bands, and eventually CDMA and GSM (requires SIM card)