TruVoIPBuzz Logo

Your ultimate VoIP resource…

All you need to know about SIP trunking and whether it is the right tool for your business [Tools]

By Alok Saboo on January 14th, 2013

We get it. You want to run a successful business, and you want to do it in a financially efficient way. After all, who wants to spend extra money when they don’t have to? That’s certainly not too much to ask, but with technology constantly changing, it can sometimes be tricky to stay ahead of the game. In your search for the cheapest technology solutions for your business, you’ve probably heard about Internet telephony and possibly even SIP trunking before. If you are not sure about SIP trunking and whether it is a viable option for your business, don’t worry. This post should answer all the questions that you may have on the topic.

What is VoIP?

VoIP - make free or cheap callsLet’s begin with VoIP, or Voice over Internet Protocol technology. With VoIP, phone calls are sent over the Internet instead of over traditional telephone lines. This in turn lowers the cost of phone calls because it is cheaper to transmit calls over the Internet rather than over traditional phone lines. It is cheap and easy to switch your telephone service to a VoIP service, but if you are running a business, you will need to consider a few factors before you make the trade.

What is a PBX?

A PBX, or public branch exchange, is the system that a business will use to route incoming, outgoing, and internal business calls. In the early days of telecom technology, a PBX was a large piece of machinery that required an attendant to operate a switchboard. Today, you have your choice of several different kinds of PBXs, both software and hardware setups.

What Kind of PBX Systems are there?

There are several types of PBX systems:

  • Analog PBX: This system was the first kind of switchboard available. This system uses an analog signal to send and receive phone calls over the traditional phone line.
  • IP PBX: Internet Protocol PBX (IP PBX) refers to either a hardware or software system that uses the Internet to send and receive calls. You can build your own IP PBX and maintain it onsite. You can buy the hardware and construct one, or you can get a free open-source program like Asterisk to build one on a software platform.
  • Hosted PBX: A hosted PBX is a type of IP PBX in which an off-site service provider manages your inbound and outbound calls. This system is maintained and hosted by your service provider at their location. Any system advertised as a hosted business solution has a hosted PBX. Your hosted PBX exists as a virtual system, available over the Internet. You can manage and control your hosted virtual PBX with any Internet-capable device like a computer or smartphone. This makes it easy to change settings and moderate your office phoning at any time, from any place.

What is SIP Trunking?

SIP trunking (Session Initiation Protocol) is a service that enables your in-house IP PBX or analog PBX to send and receive VoIP calls. You will have to find a SIP service for your PBX if you don’t want to use a hosted VoIP solution. With a SIP trunk solution, you will need a few things to get your system up and running:

  • An Internet-capable in-house PBX: If you aren’t using a hosted PBX solution, then you will need to make sure your PBX can handle and process VoIP calls. If you are using an in-house IP PBX, then you’re all set. If you are using an analog PBX, you will need to make sure you have all of the proper analog adapters.
  • A border element: This is either a firewall or an edge device attached to the firewall that will enable your PBX system to interact with the traditional analog telephone system, the PSTN (public switched telephone network). Without the border element, your SIP trunk cannot interface with analog phones.
  • A SIP service provider: There are lots of SIP service providers like, Jive, and Nextiva. These service providers usually charge a monthly fee, and they may charge certain rates for incoming or outgoing calls. These service providers may advertise that they are BYOD (Bring Your Own Device) which generally means they support SIP.
  • An Internet service: In order to use VoIP, you need a good, high speed Internet connection. You can test your Internet connection quality to see if your current setup can handle VoIP traffic.

Why Do You Need a SIP Trunk Solution for your PBX?

VoIP - make free or cheap callsA SIP trunking system is only necessary for your business if you currently have an on-site PBX, either an IP PBX or IP-enabled analog PBX. However, if your business has a hosted PBX, you do not need a SIP trunk.

Businesses that are still using a traditional phone service provider may have their own analog PBX, an actual switchboard, physically located on their premises. Analog PBX systems are considered somewhat outdated systems, but if your business still has one, then SIP trunking can bring your business into the 21st century. However, your analog PBX will need to be IP-enabled with an adapter.

Other businesses may have their own IP PBX systems. A business with an IT department or other tech support is probably more likely to use an on-premise IP PBX. Large enterprises that may prefer to handle their calls in-house, and can afford the support, space, and time required to maintain an on-premise PBX are more likely to have this kind of solution. However, depending on the number of employees your business has, and how many phone lines you need, an IP PBX system may be a more affordable system than an off-site hosted PBX.

A SIP solution would also be appropriate for a company that wants to build their own IP PBX. This would need to be a business that is up to the challenge of handling its own on-site solution, which means most likely an adventurous and tech savvy business with the hopes of running and handling its own calls.

SIP Trunking Benefits

VoIP - make free or cheap callsThe truth is hosted VoIP solutions have become so incredibly cheap, often around $20/month per extension, it may be hard to find a lot of compelling reasons to go with a SIP solution. If you are a new business without any equipment that you want to keep and use, you will probably be more inclined to go with a hosted PBX. However, if you have any old equipment you want to use, or if for any reason you are partial to an on-premise PBX, some benefits of SIP trunking include:

  • Because a SIP trunk connects your calls over the Internet, you’ll no longer need to pay pricey subscriptions fees for basic rate interface and primary rate interface connections, which will save you money in the long run.
  • Calls made over the Internet become local calls, meaning you are no longer charged hefty international and long distance calling rates.
  • If you already have PBX equipment, especially an analog PBX system, it may cost you more to get rid of your current system than to adapt it to SIP trunking. Also, using a different system may require you to purchase additional devices.Why not save time and money, and use what you already have?
  • In addition to voice data, SIP trunking supports video and instant messaging, which can help enhance the way in which your business communicates.
  • If you were using an analog telephone system, a downed telephone line could mean no phone service. With a SIP setup, there are no such worries because your phone service depends on the Internet.

SIP Providers

There are several VoIP providers that offer SIP trunking services like Nextiva, Vocalocity, RingCentral, and To give you an idea of what you might pay on a SIP trunk solution, here are some quotes from

  • Small Medium Business: This package includes five lines per trunk for $55/month.
  • Enterprise Trunking: With this package, you receive 20 lines per trunk for $200/month.
  • Call Center/Large Enterprise: This package offers an unlimited number of lines per trunk for $400/month.

SIP trunking is a valuable source that can boost your business and save you money. If your business qualifies for a SIP trunk, it could help give your business the competitive advantage it deserves.

This post has been contributed by Chloe Mulliner. Chloe is a recent James Madison University graduate with a degree in Media Arts and Design. She currently writes content for VoIP-Info in San Diego, California.

© 2015 TruVoIPBuzz All rights reserved | Please refer our Privacy Policy and Terms of Use.