How do I switch my cell phone back to digital mode?

I have a Audiovox CDM-8910 cell phone I bought just 3 weeks ago. It keeps switching between digital mode and analog mode. Several hours ago it switched to analog mode, and I can't figure out how to switch it back to digital mode, and the instruction manual says nothing about how to do it?

Can anybody tell me what I have to do to switch my cell phone back into digital mode?

Normally, phones will only switch to analog mode when there is no digital signal strong enough to use the phone. It's possible that the closest digital tower is off-line for maintenance. You'll just have to wait for it to switch back when the signal is strong enough.

If all else fails... button scramble.