IPBX or IP PBX (Internet Protocol Private Branch Exchange)

IPBX or IP PBX (Internet Protocol Private Branch Exchange) is a private branch exchange (telephone switching system within an enterprise) that switches calls between VoIP (Voice over Internet Protocol or IP) users on local lines while allowing all users to share a certain number of external phone lines. The typical IP PBX can also switch calls between a VoIP user and a traditional telephone user, or between two traditional telephone users in the same way that a conventional PBX does. The abbreviation may appear in various texts as IP-PBX, IP/PBX, or IPPBX.


 * NENA 03-502, Trunking for Private Switch 9-1-1 Service Technical Information Document (TID)
 * NENA 07-503, NENA Technical Information Document on Network Interfaces for E9-1-1 and Emerging Technologies (Archived)