Most of all, the channel banks or gateways certified by Elastix are those that use the SIP protocol on one side and some other protocol on the other (TDM, GSM, and so on). The density of these devices goes from 1 port to hundreds (analog) and from 1 to 30 or more E1/T1 ports.
These devices are very helpful in providing access to the PSTN to our Elastix server, in case we cannot have cards installed on it. These scenarios may include virtualized environments. These devices can help us integrate an old PBX into the world of VoIP and offer it services such as voicemail, SIP trunk with any provider, and remote extensions.
Let's take a look at the next diagram:
In this diagram, we see that there are two sites with a PBX in each. None of these PBXs have any VoIP capabilities. From Site A, we can take some FXO ports (analog trunks) and connect them to the analog ports (FXS) from the gateway. Then, we can configure an SIP trunk between our gateway and the Elastix...