*228 appears to be related to "new" Verizon cell towers on 3G phones. Here is an explanation from a poster tagged as "Verizon Customer Support" on a Verizon board:
Quote
Verizon
I want to ensure you are able to update your towers with the latest PRL (Preferred Roaming list). If you have a 3G device, you would need to dial *228. As tikibar1 mentioned, on 4G LTE devices, the PRL is updated with your SIM card. To ensure you have the latest PRL, you can power your phone off and remove/reinsert the SIM card once a month or so. Are you experiencing any problems?
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community.verizonwireless.com]