1927 Views 2 Replies Latest reply: Nov 4, 2010 7:42 PM by Allan Sampson
The 3GS uses a normal size SIM card. The iPhone 4 uses a micro-SIM card.
The no longer activated SIM card used with the 3GS cannot be re-activated with the 3GS. You need a SIM card adaptor for the activated micro-SIM card used with your iPhone 4 that will allow you to insert the micro-SIM card in your 3GS to use it, or you need to get a new regular sized SIM card at an AT&T store to re-activate your 3GS with your line/number.