Can I use a GSM phone on a CDMA network, and vice versa?

This is by far the most common question I receive. It is important to know which type of carrier you have, as a GSM phone can not be used on a CDMA network and a CDMA phone can not be used on a GSM network. The carrier you have will determine which network you are using. In the next posting we will examine if you can use a GSM phone on all GSM networks, and a CDMA phone on all CDMA networks.