Polycom VVX 501 Corded Business Media Phone System - 12 Line PoE - 2200-48500-025 - AC Adapter (Not Included) - Replaces VVX 500 Polycom Desktop VoIP Conference Phone - 2200-48500-025 - High Definition Audio Technology - Voice Over Internet Protocol (VoIP) 12-Line Operation / HTML5 Browser / Caller ID 3-Way Conferencing / Speakerphone / USB Port Adjustable Ringer / Volume Control / One-Touch Speed Dial / Redial