1 to 4 Line Capability</br>32 Speed Dial and 16 Intercom</br>3-Party Conferencing</br>Speakerphone; Product does not work on a digital line?? Refer user manual below.</br>Handset?? Speakerphone?? Headset and Ringer Control Volume</br>DSL Subscribers may need to us a DSL Filter</br></br>Product Description</br></br>AT&T 4 line speaker phone caller ID??call wait</br></br>Amazon.com</br></br>The AT&T 1070 Corded Speakerphone is perfect for businesses that need a Speakerphone that supports four lines. The phone is DSL compatible and has a three-party conferencing feature that lets you conduct business with three people together on three different lines. Each line has its own light indicator?? and can be set with a different ring tones for easy distinction of incoming calls. Automatic line selection means that when the phone is ringing and you pick up?? you will be connected to the one that is ringing.   <p>As your company grows?? the phone system can be ex