What is PSTN Gateway?

In this section, first, you will be informed about what a PSTN gateway is. After this, you can read about the main functionalities of PSTN gateways. You can get to know the place of PSTN gateways in telecommunication networks. At the end, there is a description about the relationship of PSTN gateways and your Ozeki Phone System XE.

A gateway is a device used for connecting two different types of networks. Signaling and media between PSTN (Public Switched Telephone Network) and IP based system are translated by third-party hardware components called PSTN gateways. The process is carried out through connection to SIP trunks or directly to terminate the PSTN (Figure 1).

what is pstn gateway
Figure 1 - What is PSTN Gateway?

The primary functionality of the gateway is to handle connections involving one or more PSTN phones. It provides signaling interworking and transforms the information received on one side to information compatible with the other side.

One or more gateways would be needed at each site if an enterprise has multiple sites. A gateway serves as a connection between branch sites and the PSTN. In such a case, a Registrar and a Mediation Server are usually needed on site because the latter can send calls for each of the gateways at each site.

Location, number and size of PSTN gateways are determined by:

  • number of users you will have
  • number of simultaneous calls or what traffic load you can expect
  • number of your sites
  • geographic location of your organisation
  • whether you are connected to the PSTN directly or via SIP trunks

Ozeki Phone System provides:

  • Transparent interworking between the PSTN Gateway and the VoIP network via SIP trunks
  • Carrying data
  • Audio extracting from the Analog phones of the PSTN before it would encode and transport it to the Internet
  • Controling the call

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