The M3903 Enhanced Telephone is a multi-line digital phone supporting up to four lines and/or features. The productivity-enhancing Call Log feature displays the incoming and outgoing calls while the fixed feature keys allow you to switch easily from handset or handsfree to headset use, personalize the phone using the Options list, and quickly access your voice messaging system.

The M3904 Professional Telephone is a multi-line digital phone supporting up to 12 lines. Enhancements include offering the largest display in its class, a Personal Directory, Call Log, and a variety of user selectable options. Support for Personal Directory PC Utility allows you to create a directory of up to 100 names and download it to the phone. The Phase 3 M3904 also supports Full Duplex Handsfree with the addition of the new Full Duplex Handsfree Accessory that easily snaps into the Accessory Connection Module.