What is FXS?

This page informs you at first what an FXS port is. After this, you can read a description about how the FXS works. You can also get to know what happens in the FXS when you make or receive a call. In the end, you can find details about the place of FXS ports in a telecommunication network like your Ozeki Phone System.

FXS's or Foreign eXchange Subscribers are the plugs on your wall, from where a cable runs out towards an FXO port in your phone or fax machine. It delivers ring voltage, battery current and dialtone to your FXO device, or the device connected to your FXO port.

what is fxs
Figure 1 - What is FXS?

Working process of these ports:

(as shown in Figure 1 above)

  • Somebody sends a data (which can be audio, video, anything) in the PSTN (Public Switched Telephone System, or the classic telephone system).
  • That data is transmitted to the FXS port,
  • and goes further in a cable, which is connected to
  • an FXO adapter.
  • From there, it arrives at the Ozeki Phone System server
  • and then it finally gets to its destination: either a VoIP phone or the Internet.

If you wish to make a call

  1. Once you pick up your fxo device, your fxs port will be notified about it.
  2. On your device, you dial a number which is sent to the FXS plug then to your service provider.

If you receive a call

  1. A call arrives from your service provider to your FXS port, which sends a sign to your FXO device.
  2. You hear a ringtone from your phone.
  3. Once you answer the call on the FXO device, it will be sent to the FXS port, then to the service provider. It sends it to the desired FXS port, then to the FXO device of the person who wishes to get in contact with you.

FXS is always in connection with an FXO or Foreign eXchange Office, which is the plug on your phone or fax machine. A PBX can be installed between your FXO and FXS ports. A PBX, or a Private Branch Exchange functions as a server that can connect local calls between extensions, and outgoing-incoming calls to the local network.

Via the Internet, the PBX will be able to connect your analog phone system or a traditional PBX to a Voice over Internet Protocol server or to each other. The Voice over Internet Protocol, or VoIP is a protocol that directs transmission of voice data packets over the Internet.

An adapter is a device that can synchronize two or more technical devices. You will need to obtain one, more specifically an Analog Telephone Adapter (ATA). ATAs connect the analog and the digital telephone systems. In this case, if you would like to connect your traditional phone to the Internet. Through an ATA, direct communication comes to pass between an analog phone and a VoIP server. You don't even need to install any further programs.

Your FXS can only reach the highest capacity and so the most data with the best quality, if your server gives them to you. Ozeki Phone System will. Our customers are always satisfied with our next generation services.

Read the following pages for further information:

For a better understanding, please watch our video:

What is FXS? (Video tutorial)

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