Sip Trunks – The Ultimate Guide

Your Guide to Sip Trunks 

Is your business still using the traditional PSTN to make phone calls? The modern telecoms industry is all about SIP Trunking, which will soon replace this outdated technology. You should be looking into how it works so you can prepare for when VoIP becomes more widespread and take advantage of any opportunities that arise from switching over to SIP Trunks

What is SIP Trunking? 

SIP is just one of the many ways that people can use to communicate with each other. It functions similarly to how HTTP does, converting voice signals into data so it’s easier for devices used by callers to decode them.

SIP stands for Session Initiation Protocol and is a way to make end connections over the internet. The trunking element is actually just what most people think it means – an old word used in reference to phone lines shared between users. Modern trunking is an internet-based connection that allows you to connect your phone system with the PSTN.

To ensure your business can keep up with the latest technology, you should use SIP Trunks to connect from an exchange on a PBX. This will allow it to stay in contact and communicate seamlessly with other things going on at home or abroad such as Voicemail Systems that work through Voice Over Internet Protocols (VoIP).

Who Should Consider Them?

SIP Trunks are an absolutely essential component of any business and should be chosen carefully. There’s plenty to think about when choosing how you want your phone system deployed, from the type of IP PBX that will best suit your needs all the way down to what kind of hardware is required for installation in either case. 

Using on-premise hardware combined with SIP trunks is a great fit for companies that have these characteristics:

IT Managers and Telephony Specialists in House 

You can have a PBX system up and running in no time with the right professionals. On-premise systems are expensive, however, they require experts who know how to set them up for maximum efficiency so it’s best if you hire an agency or managed service provider instead of doing this yourself. 

Significant Call Volume

Businesses with a high volume of calls need the flexibility and cost-effectiveness that SIP Trunking provides. Call centres, for example, sales or support hubs, are highly likely to use complex PBX systems backed by specialist services like voice over IP (SIP). Getting an off-the-shelf provider who is willing/able to work out details tailored specifically towards your needs can mean serious savings in the long run but comes at higher upfront costs which may make it difficult when planning ahead – especially if they’re not entirely sure what will be required down the line.

VoIP providers that offer hosted PBXs may be an option for certain businesses, as they allow the same range of features and reliability with almost none of the maintenance or setup cost. A good VoIP provider should always help you choose a sizing up your needs that match those specifications. 

SIP Trunks vs SIP Channels 

“Trunk” cables were previously used to link from a local telephone exchange, but with the internet this process became virtual. A trunk is now just one of many assigned channels in our modern telecommunications world and we need them all for business purposes! The number will depend on how many simultaneous calls you want your company making or receiving. A good SIP provider will help you calculate this.

Channels are a key component of understanding the makeup and function of trunks. Every SIP trunk contains many channels, which each act as virtual versions or old fashioned telephone lines allowing two concurrent calls at once; one incoming/outgoing. The number of channels your business needs is affected by how frequently calls are coming in. If you have a lot of concurrent clients, it’s best to invest in more than two channels so that each channel can be used individually instead of being shared with another call at the same time.

Why are Businesses Using Them? 

Businesses that still use ISDN in their business are at risk of losing customers to other companies who take advantage of the latest telecoms services. However, there is hope for these firms as switching over can lead to many benefits including lower costs and more reliable infrastructure due to IP-based networks which provide better quality than old analogue systems do. 

Cost Saving 

ISDN and traditional telephony can be costly for businesses because they often end up using capacity that is not used. SIP Trunks, however, provide accurate billing based on usage; plus the price of a line rental or calls made with your provider usually falls when you use it more frequently than less frequent contact methods like voice mailboxes. This becomes even more important if there are high outbound call volumes such as those found in sales teams or consultancies – which means these types of companies should seriously consider an IP PBX system instead. 

Geographic Flexibility 

SIP Trunks are perfect for international-based customers or suppliers, who want to keep the same number at their new location. You can move offices and still have access to your phone line with SIP trunks. 

Preparing for the Future

ISDN has been an excellent way for businesses to combine voice and data services with traditional lines. In the modern age, connectivity is king; it’s what makes or breaks your company from day-to-day operations! Business telephony revolves around power and reliability so you need a firm internet connection plus efficient service plans that will get everything done in time – IP based PBXs are necessary no matter where they’re located (on-premises/cloud).


Trunks are easy to scale up or down, depending on usage. For example, if your organisation suddenly experiences significant growth don’t worry about physically installing new ISDN lines as it is simple and quick. 

Unified Communications 

SIP Trunks are the cornerstone of any modern communication system. SIP into your phone, computer or tablet to access all forms of incoming and outgoing calls, texts messages as well as emails with just one easy interface. 

Trunking provides a virtual, rather than physical installation and so it can be set up quickly. In most cases, businesses do not need additional equipment for their internet connectivity because they already use the same infrastructure as necessary with no changes needed at all.

SIP trunk providers are the answer if you need assistance with your phone system. They can help get a modern IP PBX and fast, reliable internet connections for an affordable price. 

What Do I Need to Consider? 

Before installing your business with SIP Trunks it’s important to keep some key factors in mind; 

How many current calls will you need? 

Remember to account for the number of channels you’ll need when it comes time to sign up. This includes both inbound and outbound calls, so make sure that your business has an understanding of what their concurrency stands at before committing. 

How many minutes will you need? 

It can be hard to figure out how many calls you should make per month. One way of figuring this out is by looking at what type of rates are offered for different volumes, but sometimes it’s cheaper just to buy making more than one call at once. 

How many new numbers will you need? 

Sometimes it’s worth considering getting new numbers if you are opening a different office in another geography. VoIP allows for the use of full benefits using SIP trunks, which can allow small businesses to appear more efficient than they really are and create international support numbers with ease- all at very low cost. 

Are you porting any existing numbers over? 

With a pre-existing business number, you can keep your customer database. However if for some reason the number is lost or outdated then porting must be performed in order to maintain contact with customers who are familiar with using that specific line for sales and support needs. This part of the SIP trunk process takes slightly longer but ultimately allows new numbers which will save time on repeat calls between departments like billing and marketing alike.

Share this post