Now that we know what a VoIP Gateway is, we can try and choose the right gateway depending on the need of the end client. To make it easier, we'll simply take the most used scenarios:

  • Connecting a PSTN line to an IPBX
  • Connecting analog devices to an IPBX
  • Soft migrating to a VoIP solutions
  • Connecting a PBX to a SIP trunk

Once you know the scenario and the number of ports you need on the gateway, use our configuration wizard to design the right beroNet gateway.

Connecting a PSTN line to an IPBX

In this case, the client has a traditional telecommunication connection, not compatible with VoIP, that he wants to connect to an IPBX, which is not compatible with PSTN. Here, the client has either analog lines or ISDN ones.

ISDN lines

We know this for sure: your client needs an ISDN gateway. If they also have analog endpoints, check below. In ISDN, there are two kinds of lines: BRI (basic rate interface) and PRI (primary rate interface also called E1 in Europe and T1 in the USA).

  • With one BRI line, we can make two simultaneous calls
  • With one PRI line, we can make thirty simultaneous calls

You then either know if the end client has so many BRI / PRI lines or you know how many simultaneous calls the clients can make.


  • The client can make 8 concurrent calls. He most probably has 4 BRI lines. You then need a 4 BRI Gateway.
  • If the PBX has 2 PRI lines, you need a 2 PRI Gateway.


choose VoIP Gateway diagram ISDN lines to IPBX


Analog lines

In order to connect an analog line to an IPBX, you need an FXO Gateway. With one analog line you can make only one call. It is then easy to find out how many ports you need to have on the gateway.


Choose VoIP Gateway diagram analog line to IPBX 



Connecting analog devices to an IPBX

To connect analog devices to an IPBX, you need an FXS Gateway. The number of ports you need depends on the number of analog devices you want to connect to the IPBX.
Here are a few analog devices you can connect to an IPBX by using a VoIP Gateway:

  • phones
  • fax
  • doorphone
  • payment machines
  • alarm systems

If you want to connect an other analog device, just contact us and we'll check if it works.

With the beroNet hybrid module, you can connect 2 analog devices and 2 BRI lines to an IPBX



Choose VoIP Gateway 3



Soft migration

For a soft migration, you usually need to connect a traditional PBX, and IPBX and PSTN lines to the gateway. Once again, the technology we will use in the gateway depends on the technology used on the PBX:

  • ISDN: the beroNet ISDN Gateways can work in NT or TE meaning that they can simulate the ISDN provider or the PBX. If the PBX used in the soft migration is an ISDN one, then you need to find out the type of lines it is connected to  (BRI or PRI). Once we know the type of lines and the number of lines we know the kind of gateway we'll need.
    Example: if the PBX has 1 PRI, you will need a gateway with 2 PRI (one port in each direction).


Choose VoIP Gateway diagram soft migration 


  • Analog: You will need a gateway with FXO and FXS ports. You will connect your analog provider line to the FXO ports and the PBX to the FXS ports of the gateway. You only need to find out how many ports you need.


Choose VoIP Gateway diagram about analog soft migration Analog soft migration



All-IP scenario

In this case, you want to connect your traditional PBX to a SIP trunk. Once again, the technology used in the gateway depends on those used by the PBX:

  • ISDN: Find out if the PBX is using BRI or PRI lines and how many. If you wish to get rid of the provider line, the gateway needs to have as many ports of the right technology as the PBX has connections


Choose VoIP Gateway diagram about ISDN All IP Connecting ISDN PBX to VoIP


  • Analog: you will need an FXS Gateway. The number of ports in the gateway depends on the number of concurrent calls the PBX can make.


Choose VoIP Gateway diagram All IP analog Connecting analog PBX to VoIP



beroNet modular gateways enable you to create the gateway of your choice depending on your clients needs.



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Jean-Eudes Ambroise

Author: Jean-Eudes Ambroise

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