My iphone which is second hand shows no service but sim is inserted?

My iphone which is second hand shows no service but sim is inserted?

Sounds like it could be barred, always that gamble when you buy a second hand phone

It's your phone shown "no service" message while inserting sim? Yes means, Try powering off the device and removing the battery if possible > then remove the sim card and leave it out for a minute > reinsert the sim card > power on the device. If your problem persists, there may be a chance to your phone is restricted by some network carrier, So try to unlock your phone. For unlocking visit http://www.superunlockcodes.com/apple-iphone/rs5wp9/

Many thanks