Video Communications | Features/Function Enhancements

The older generation of PBX station users may remember their first introduction to the videophone at the 1964 New York World’s Fair. Several generations of PBXs have come and gone since 1964, but PBX-based desktop video communications is still a work in progress for most customers. The first major attempts at desktop video communications behind a PBX system occurred during the early 1990s when ISDN BRI options became available. Using both BRI bearer communications channels per video call (128-Kbps transmission rate) provided a fair quality of service, but a killer application for the video option never materialized, and desktop video behind the PBX is rarely implemented today. Desktop video communications today is based primarily on LAN or supported by dedicated trunk circuit facilities.

Lucent Technologies attempted to revive interest in PBX-based video communications in the mid-1990s when it introduced two Definity PBX options designed to support voice calling features on video calls. The MultiMedia Communications Exchange (MMCX) was a server-based system designed to support H.323 mixed-media calling (voice, data, and video). The MMCX provided some basic calling features, including dial plan, conferencing, and call forwarding, to LAN-connected workstations used for video communications applications. The MMCX could also support traffic between PBX ports and LAN peripherals, and a Q signaling (Qsig) link would provide a higher level of PBX system features to the LAN workstations. Another PBX option was called MultiMedia Call Handler (MMCH), which was designed to apply a limited number of voice calling features to ISDN BRI video workstations conforming to H.320 standards. Neither the MMCX nor MMCH offerings gained market acceptance, although the MMCX product was later modified by Lucent and reintroduced as its first Internet telephony gateway product. The IP gateway was further redesigned as an internal IP trunk interface card for the Definity PBX. The concept of the MMCX, a call processing server for LAN workstations, could be considered an early version of today’s emerging IP-PBX systems. Although no IP telephones existed when the MMCX was announced, LAN-based voice communications using a video workstation equipped with a microphone and speaker were supported.