Grandstream GXP2020 6 SIP Line Backlit VoIP IP Phone 7 Prog Keys 2 RJ45 BrandNew6 lines indicators with individual SIP account profiles 7 programmable hard keys and 4 XML programmable context sensitive soft keys Multi line support of up to 13 call appearance lines with dual color LED indicators Expandable to additional 112 lines through expansion key modules Support Caller ID display or block, per call or permanent Call waiting, hold, mute, transfer (blind or attended),forward, and more Multi party conferencing (up to 5 way) 5v