Specifications

iPhone 4 Symptom Charts — Connectivity Issues 67
2012-02-21
Deep Dive
Check Result Action
1. Identify carrier type.
Identify whether the carrier
uses CDMA or GSM.
Is the device running on a
CDMA or GSM network?
CDMA Go to step 2.
GSM Go to step 3.
2. Contact cellular carrier.
From another phone, call the
cellular carrier and verify that
the user’s account is active.
Also perform any updates
suggested by the carrier.
Is the cellular issue resolved?
Yes Issue resolved.
No Go to step 7.
3. Verify that SIM is not locked.
Go to Settings > Phone > SIM
PIN. If SIM is locked, unlock it.
Also see Apple Support article
HT1316: iOS: Understanding
the SIM PIN.
Is the cellular issue resolved?
Yes Issue resolved.
No Go to step 4.
4. Reseat SIM card.
Using the SIM removal tool,
eject the SIM card tray and
reseat the SIM card.
Is the cellular issue resolved?
Yes Issue resolved.
No Go to step 5.
5. Test known-good SIM card.
Substitute a known-good SIM
card.
Is the cellular issue resolved?
Yes Issue resolved. User should contact
carrier to verify account status.
No Go to step 6.
6. Contact cellular carrier.
From another phone, call the
cellular carrier and verify that
the user’s account is active.
Is the cellular issue resolved?
Yes Issue resolved.
No Go to step 7.