Do I Need an Asterisk (FreePBX) Server?

Updated by Bryan Jones


This article addresses a common question about new VX system installations: is an Asterisk server required? To be clear, no, an Asterisk server is not necessarily needed for every VX installation, although it is an option available when needed. Please continue to read this article for more information.

Information provided here regarding "Asterisk" or "FreePBX" servers refers only to Telos-commissioned FreePBX (Asterisk) servers used with Telos Alliance telephony products. While these are third-party servers and software, we can provide limited pointers and advice (like this article) under regular support.  

What is an Asterisk server?

An Asterisk (FreePBX) server is one type of VoIP PBX server. FreePBX is a GUI (or wrapper) for Asterisk, the main software engine providing PBX capabilities. While they are not the same, these terms are often used interchangeably, which is okay for this article's scope.

Many other types of VoIP PBX servers are available today; some of the most popular brands are Avaya, Mitel, and Cisco. While the formerly listed brands all offer only commercially-supported paid products, Asterisk (FreePBX) is open-source software.

What is a VoIP PBX?

A Voice over IP Private Branch Exchange is a system that connects VoIP phones to the Public Switched Telephone network. Asterisk is one type of VoIP PBX; other popular commercial options are available from Avaya, Mitel, and Cisco. Generally, these are deployed as on-premises servers.

Additionally, many hosted VoIP PBX services exist, such as Vonage, Nextiva, and Mitel Cloud. These services host your VoIP PBX in the cloud (using a Software as a Service [SaaS] model) and typically provide connectivity over the top (OTT) of your existing public internet connection.

There are numerous variations of this, such as an incumbent local exchange carrier (ILEC) like AT&T or a competitive local exchange carrier (CLEC) like TPx providing SaaS VoIP PBX service on a managed high quality of service (QoS) circuit.

Do I need to use some type of VoIP PBX with VX, whether it is Asterisk or something else?

Yes. VX is designed to register extensions to a VoIP PBX of some kind, whether commercial or open-source, in the cloud or on-premises, etc. The VX is not a VoIP PBX itself and does not have most of the VoIP PBX capabilities. VX is designed to connect to and leverage the power of a VoIP PBX.

In other words, the VX is generally not designed to connect to a SIP trunk coming directly from a telecom provider. A SIP trunk connects to a VoIP PBX, and the VX connects to the VoIP PBX as well. The VoIP PBX sits in-between the SIP trunk and the VX.

The diagram below may help determine if a new VoIP PBX is needed.

If you are unsure, the questions asked in this diagram can be answered by consulting with your IT team, telephony team, or managed service provider handing technology for your facility.

Common scenarios where an Asterisk server may be not be required.

On-Premises VoIP PBX
  • VoIP PBX allows third-party (generic) endpoint registration
  • Additional PSTN redundancy is not required
Hosted VoIP PBX
  • Hosted VoIP PBX allows third-party (generic) endpoint registration
  • Additional PSTN redundancy is not required
By "third-party" or "generic" endpoint registration, we mean, would a branded phone system allow non-branded phones to register. A specific example might be a Cisco phone system. If only Cisco phones are allowed, then the answer to the third-party question is no.

Some systems require specific licenses for generic endpoints.

Common scenarios where an Asterisk server may be desirable or required.

  • REQUIRED - When no VoIP PBX exists and using a SIP trunk is needed, an Asterisk server is necessary to convert the SIP trunk into third-party extension registrations for VX.
  • DESIRABLE - When redundant connectivity or load balancing for inbound or outbound calls is required, an Asterisk server may be necessary to connect to multiple telephony providers or existing office PBXs.
  • DESIRABLE or REQUIRED - When broadcast telecom connectivity needs to be independent of general office telecom, an Asterisk server connects to a broadcast-dedicated SIP trunk, essentially converting its trunk into third-party extension registrations for VX.
  • REQUIRED - When connectivity to Primary Rate Interfaces (PRIs) or Plain Old Telephone System (POTS) lines is needed, an Asterisk server may be equipped with the proper interfaces to convert these types of legacy circuits to VoIP for the VX to use.

An Asterisk server sounds like a good fit for my situation, but I've never set one up. Can this be handled for me?

Yes. Telos Alliance is happy to provide advanced, dedicated support and training on a VX and FreePBX system through various paid TelosCare Service Level Agreement options or a la carte via our Dedicated Remote and Onsite Configuration service. We can also recommend pre-built Asterisk servers for purchase. Please ask your Telos dealer for more information or use the Contact Us link above for more information on these options. We can guide you through this entire process.

Additionally, some Telos dealers independently offer Asterisk configuration, training, and support. Your Telos dealer can recommend the best options for your situation.

I'm considering VX, but I'm still not confident about providing the proper telecom connectivity for it. Where do I go from here?

Please get in touch with your local Telos dealer (or contact the Telos Alliance sales team who can assist you in finding your local dealer). After chatting with you to understand your specific situation and needs, our dealer can provide expert recommendations, or connect you to a telephony consultant at the Telos Alliance for advice.

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