Up to 10 handsets / 10 VoIP accounts / 20 parallel calls and 6 repeaters per base station, Support LDAP/Remote Phonebook, Compatible with Yealink W73H/W59R/W56H/W53H/CP930W/DD Phone, Handset upgrade: OTA (Over-The-Air)/No Perception, Noise Reduction System, Support Opus and PoE