The Samsung S5600 is a quad-band smartphone originally released in 2009. The phone features an HSDPA high-speed 3G cellular-data connection, speakerphone, messaging and a 3.15-megapixel digital camera. The Samsung S5600 is normally sold with a carrier lock that prevents the use of the phone with another carrier's Subscriber Identity Module (SIM) card. You can, however, unlock the Samsung S5600 so that you can use the phone with another cellular-service provider.
Remove the old SIM card from your Samsung S5600 by sliding off the phone's back cover and removing the card from under the battery. Insert the SIM card from your new carrier. Place the battery back in the battery compartment and replace the back cover of the phone.
Call your existing cellular-service provider and request the unlock code for your Samsung S5600. In the United States, cellular-service providers will generally give you the unlock code for free if you have an account in good standing. Alternatively, you can purchase the unlock code from a company that specialises in selling unlock codes for mobile phones.
Type "#0111*CODE" using the Samsung S5600 keypad. Replace "CODE" with the unlock code. Your phone is now unlocked and will work successfully with the new SIM card.
If you enter the unlock code incorrectly too many times, you can permanently disable the Samsung S5600.