The Yealink T28P is a top of the range business VoIP phone, featuring high quality telephony features including a 320 x 160 graphic LCD screen with 4-level grayscales, 6 VoIP accounts which are Broadsoft / Avaya/ Asterisk validated, and the TI TITAN chipset. Yealink SIP-T28P Features 6 SIP Accounts 320x160 White Backlit LCD Display 4 Level Grayscales 16 Programmable Keys Logo Customisation on Screen Expansion Keypad Available Power over Ethernet 3 Way Conference Calls Speakerphone MP3 Ringtones and Voicemail. Call Hold, Waiting and Transfer.