As of the writing of this article (Jan. 2013) there are no telephones made by ATT that are compatible with ATT 945. The ATT945 telephones were discontinued several years ago. You have two options:
1. Buy newer ATT phones.
2. Purchase any regular analog phone. (You will not have all the features as the ATT 945 but you can use other phones without having to replace all of the older ATT 945)