The Primary Rate Interface (PRI) is Hybrid communication Module interfacing Zycoo PBX and the ISP and establish a high efficient Office Telephony over VoIP in UAE. PRI is a standardized telecommunications service level within the Integrated Services Digital Network (ISDN) specification for carrying multiple DS0 voice and data transmissions between a network and a user.

The Zycoo PRI module have 1 RJ45 port and can be slide to one of the module slot in office IPPBX like U100 ,U80

The Primary Rate Interface (PRI) consists of 23 64-kbit/s B-channels and one 64-kbit/s D-channel using a T1 line, often referred to as "23B + D", (North American and Japanese standard) or 30 B channels and two D-channels using an E1 line (Europe/rest of world), often referred to as "30B + 2D". A T1 Primary Rate Interface user would have access to a 1.472-Mbit/s data service. An E1 Primary Rate Interface user would have access to 1.920 Mbit/s data service Larger connections are possible using PRI pairing.