Polycom SoundPoint IP 550 4-line HD voice hartsook 12 years ago click for details The Polycom SoundPoint IP 550 is a four-line SIP desktop phone that brings lifelike richness and voice quality to phone calls. MSRP $355 Related PostsPolycom SoundPoint IP 321 and 331Year-End Highlights and Predictions for 2015North Korea Attacks! Cybersecurity Notes for Small EnterprisesTelnexus Cloud Fax Documentation