Connect up to two cellular lines and two landlines with this cordless system. Store 6000 directories from up to 4 different cell phones. Digital Answering System - one for each line. Caller ID with signal. Handset and base speakerphone. Expandable system up to 12 handsets (uses TL86003 accessory handset). AT&T Softphone Call Manager merges Microsoft® Lync®, Skype™, VoIP and landline telephone services for flexible, full-access communication on one convenient system.