More importantly for whom the phone does not ring, like telemarketers, and other undesirables.
The Treo phone has a nice option. You can select to have the phone not ring for people not in your contact list. Since up to now all my cell phones had been Treos I thought this was an option on all phones.
I almost returned my new Mogul to the store when I found it didn’t have that option. However there is an easy fix and it should work on just about any cell phone.
First you need a ring tone that is silent. This was not easy to find. (Silent.wav )
Install the silent ringtong in your ringtone directory. ( My Documents/My Ringtones on Windows Mobile )
Assign it to be the main ringtone for your phone.
Lastly assign a ringtone that makes noise to all the contacts in your phone. ( Tone Manager will let you do bulk updates on Windows Mobile )