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Subscription Based SIP Trunking Provider

Unlock In-House SIP Service Capabilities

Discover a convenient, internal IP PBX management solution. If you have an IT team or use managed IT services, an on-site SIP trunk solution may be a good fit for your company. VoiceSpring’s premium SIP trunking subscriptions allow you to save money and manage your PBX system in the office. However, we require your appointed IT provider be certified on your company’s IP PBX system.

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Leading SIP Trunk Provider for Self-Service Cloud PBX

VoiceSpring's SIP trunking licenses are the ideal SIP PBX solution for system-certified IT experts looking to manage an existing PBX system on-site.

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Cloud Based

Connect your existing SIP-enabled PBX system to our secure cloud servers.

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Self-Managed

Appoint your own system certified IT provider or employee to manage your system.

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Secure & Reliable

Redundant server infrastructure with a minimum 99.25% uptime.

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Cost Effective

Decrease your company's telecommunication expenses with no capital investment or additional on-site equipment.

Our Key to the Cloud. Your Key to Success.
Start with a quote from our sales team.

Learn About SIP Trunk Service


What Does SIP Mean?

Let’s start with the basics. SIP is short for Session Initiation Protocol. SIP is the standard VoIP protocol used to connect, transmit and end a voice call.

What is a VoIP SIP Trunk?

Since a SIP trunk is a type of VoIP standard, its job is to connect voice calls over the internet. A SIP trunk makes it possible for two phones to “speak” to each other by providing a common set of rules, so voice “packets” can be exchanged and handled correctly over an IP network. For more details, we encourage you to read the Wikipedia article on SIP.

What is SIP Trunking?

SIP trunking is a type of VoIP service. SIP trunking uses SIP rules to hook your IP PBX, or private branch exchange, into the public switched telephone network, or PSTN, over your IP network.

What Does a SIP Service Provider Do?

To use SIP service, a business needs a SIP trunk to connect to PSTN. Most SIP service providers offer hosted SIP service, such as VoiceSpring’s cloud hosted business phone systems. However, some VoIP providers also provide stand-alone licenses, or SIP service subscriptions.

How Does a SIP Trunk Work?

A SIP trunks connects your IP PBX to your ITSP, or internet telephony service provider. It uses meditation servers to manage voice and signals sent to a business phone system. It works in one of two ways:

  1. Using lines to connect to IP traffic.
  2. Using a VPN, or virtual private network, over the internet.

Is SIP Trunking the Right Solution For My Company?


Work Smarter, Not Harder

Combining data and voice in one IP connection, can speed up your network and take some of the load off your IT team.

Waste Not, Want Not

Only buy the amount of SIP trunks you need. Plus, you can use your existing PBX. That sounds like a great business decision!

The Benefits of Cloud SIP Trunking

Taking the place of landline service, SIP trunking - and VoIP as a whole - has saved money for a lot of businesses over the years. It has also added a whole new group of features and capabilities, such as:

  • Directory listing and assistance
  • Local and long distance calling
  • Mobile and landline phone numbers
  • Email and SMS integration
  • e911 to make emergency calls

SIP trunking in the cloud does not require you to invest upfront. This solution offers several benefits, which include:

Consolidate Voice and Data Under One IP Network

Access multiple virtual streams, instead of paying for voice and data separately. This will cut your costs for maintenance and operations.

Expand When You Want To

Eliminate growth issues. Scale at your own pace. SIP trunking makes it easy to increase or decrease users by allowing you to add or remove licenses as needed.

Upgrade Your Service Level With More Internet Bandwidth

When it’s time to turn your service up a notch, all you have to do is increase your bandwidth. This is much easier and cost effective than footing the bill to install new hardware and maintain that equipment. SIP trunking also allows you to buy bandwidth for less and increase a little bit at a time.

Elimination Extra Fees

SIP trunks can replace your PSTN gateway with a direct connection to your ITSP. Those lines usually come in packs of 24 or 32. The service that takes their place is much more affordable, so you can add those costs back to the books as well.

Turn All of Your Calls Into Local Calls

SIP trunking carries your calls over the internet, which means you can place long distance calls as free, local calls. In some cases, even international calls can be sent to a point close to the number that was dialed, which will make them local calls as well. In addition, you can obtain local numbers in any area. These will show up as local calls, which customers tend to trust more than calls from 800 numbers. However, you still have the option to use an 800 number if you so choose.

Get a Huge Return on a Small Investment

For little to no investment cost, SIP trunking affords a very high ROI - and fast!

Choosing the Best SIP Service Provider for Your Business

It is wise to check out all your options, to be sure your SIP trunk service meets the needs of your business. We suggest you answer these questions before you start your search:

How many calls do you need to be able to handle concurrently?

This is the number of channels your business will need to ensure all calls can be handled at the same time. Since SIP trunks are easy to scale, you can add or remove them later if you find you have too many or too little channels. In this case, it’s better to have too many than not enough. So, if you’re not sure, it is best to start with the number of lines in use when you are most busy.

Does your call volume stay the same each week or does it change on a regular basis?

Some providers allow you to make use of additional channels if you exceed the number you chose in the first question.

Do you need to be able to add new users fast or often?

This is important to consider when choosing your phone system, as some PBX providers may make it easier to buy more phones when you need them. This has an effect on your ROI, as well as your operations.

Tips for Setting Up SIP Trunking


SIP Trunking with Your Phone System

SIP Enabled PBX


Many businesses use IP PBX systems for more flexible communication, such as the ability to use shared lines.

Traditional Phone Systems

Some companies use PSTN gateways to connect phone systems which are not VoIP capable. This allows you to save on your phone system, but still reap the benefits of SIP trunking.

Preparing Your Network for SIP Trunking

Before your IT provider sets up your system, some decisions need to be made in regards to your network. These include whether you will use dynamic or static IP addresses, how much bandwidth you will set aside for Quality of Service, and how you will configure your firewall. You may need to upgrade your internet package in order to have enough bandwidth to use your new phone system without slowing down your internet speed.

Order Static IP Addresses


Using a static IP address is considered “best practice” when setting up SIP trunking. Here are a few reasons why:

  • Prevent Issues With Voice and Video Delivery - Your audio and video travel over the internet using RTP, or Real-time Transport Protocol. Here and there, RTP may stop traffic, which means inbound voice calls will not come through. Each static IP address has its own host name, so it will always be able to find it, thus eliminating conflicts.
  • Take Advantage of Mobile Apps - If your cloud PBX offer mobile applications, a static IP is required for them to function properly.
  • Access Your System Remotely - Using a static IP address makes it possible for an authorized user to manage your system off-site. You may be required to use a static IP if you outsource your IT services.

Contact your internet service provider (ISP) to find out how to buy a pack, or multiple packs, of static IPs.


Establish Quality of Service

QoS gives priority to your voice traffic by setting aside a set amount of bandwidth at your router. Most business grade routers come with network QoS.

Configure a Firewall

Any business that uses the internet should use a firewall to protect it. It is the only way to ensure your network is secure and able to keep out threats to your business, such as hackers and viruses. When using SIP trunking, you will need to be sure your firewall is set up the right way. Otherwise, your SIP service may not perform well.

Set Up e911

When you make and emergency call, e911 attaches a physical address to your phone number. This VoIP feature keeps your business and employees safe, so we highly recommend having it.

How SIP Trunking Stacks Up


What Is the Difference Between SIP Trunking and VoIP?

VoIP and SIP are not as different as they might appear to be at first. SIP is used to implement VoIP, so the two services actually work as a team to transport voice data over your IP network.

What Is the Difference Between SIP Trunking and PRI?

PRI stands for Primary Rate Interface. In use for more than 40 years, this service is also known as “traditional telephony.” PRI uses copper phone lines to transfer voice data, while SIP trunks rely on your IP network.

In the US, standard PRI uses a T1 line, or PRI circuit. One cable can carry 24 channels. 23 are used for voice channels, which are able to handle one phone call at a time. The last channel is used to enable caller ID and other system functions.

PRI uses circuit switching instead of packet switching, which is used by SIP trunking. It send voice data to a conventional phone company as a series of electrical pulses. Adding lines or hardware to a PRI phone system requires on-site service, so the cost may rise fairly fast.

Compare SIP Trunking to Cloud Hosted Business Phone Systems


SIP Trunks

  • Limited features
  • System certified IT provider required
  • Managed by your IT team
  • Bring Your Own Device (BYOD)

Cloud PBX

  • Includes all features
  • Not required to have a tech on site
  • Managed by your ITSP
  • Buy or lease a premium business phone system

As you can see, cloud based phone systems are by far the easiest option in terms of setup and management. However, it would be difficult to create a list of pros and cons, as the value of each service is open to interpretation. Whatever you decide is best for your business, VoiceSpring is here to help. As a leading business VoIP provider, we invite you to call us at (866) 654-1800 to review options, ask questions, or just say hello.