A video conference gateway is a expensive piece of equipment that allows unsupported protocols to translate and connect up. So for example a piece of video conference equipment that uses SIP can connect to a H.323 compatible video conference device. The gateway will handle all call setup and tear down. It can allow your video conference equipment to support both IP and phone numbers for dialing. Multiple people can all connect up to a gateway to have a video conference, when no single individual has enough bandwidth to host the entire conference. Video conference gateways tend to be extremely expensive to purchase and operate. There are providers out there that can and will provide this service for you, if you are willing to pay them to use their equipment.

Troubleshooting a video conference gateway can be really hard in some cases. There are classes you can take that will teach you how to do this. Both Avaya and Cisco offer classes on the subject. Usually the gateway will be accompanied by software that you can install on a windows/linux/unix machine that will help you with configuration and setup.