Gateway
A gateway is an optional element that can be implemented within the H.323
deployment. It is an endpoint on the LAN that can provide real-time, two-way
communication between H.323 terminals or other gateways. It is also capable of
using the LAN and other ITU terminals located on the WAN by using H.425
and Q.931 protocols.These gateways are not required if there are no connections
to other networks.You will use these gateways when you need to:
Create connections over analog PSTN terminals
Create connections with H.320-based terminals across ISDN circuits
Create connections with H.324-based terminals over a PSTN networks
Gateways can translate between H.323 conferencing endpoints and compliant
terminals, H.225 to H.221, or between communication procedures, H.245 to
H.242.These gateways can also translate between audio and video CODECs,
performing call setup and termination on both sides of a network. If you configure
the gateway properly, it can also support H.310, H. 321, H.322, and V.70
standard terminals.