Thinking of moving over to VoIP? What you should know

What is VoIP and SIP and how many lines do I need?

VoIP stands for Voice over IP (Internet Protocol), which is essentially just a phone call over the internet instead of using the traditional PSTN and ISDN phone networks that have been in place for most of the century in various forms. While these older technologies have served the world well during this time, the benefits of VoIP are vast, from price, to call quality, availability, flexibility – the list goes on and on and on. The adoption of VoIP by both businesses and consumers has been so rapid that BT, the main provider of these telecommunication services, stopped taking any further orders for ISDN lines this year and have plans to switch off the existing network by 2025.

SIP stands for Session Initiation Protocol and is the communication technology used by VoIP to do all the complex networking and routing through the internet to connect you with the person at the other end of the phone. A SIP trunk is required to be able to communicate with other phone systems external to your company and SIP lines are purchased to allow a business to make multiple simultaneous calls if that’s what is required. A minimum of two is recommended, but more can be purchased as and when they are required to give the system sufficient availability.


Do I need a dedicated line or business line for call quality to be sufficient?

Whilst a reliable broadband connection is necessary for a VoIP system to function correctly, preventing calls from being dropped mid conversation, the speed of your line is not as important as you may think. The vast majority of business premises have broadband connection speed (bandwidth) of at least 10Mbps download and 3Mbps upload. A more realistic figure are speeds in the range of 50Mbps download and 10-20Mbps upload. To put this into context, for a VoIP call to have an acceptable level of quality, the bandwidth required for each simultaneous call is 100Kbps, which equates to 0.1Mbps. Obviously most online traffic in and out of a company is to do with web access, email and document transfer, but with the requirement of VoIP connections being so low, allowing for enough bandwidth allocation isn’t necessary in most working environments. On top of this, most business grade routers and firewalls provide a feature that can be enabled called QoS (Quality of Service) which allows an administrator such as ourselves to provide a dedicated bandwidth for VoIP traffic, ensuring that even during times of high bandwidth use, call quality is never affected.


Will I need to purchase devices to receive calls?

There are three main methods of making and receiving calls through your VoIP system, and finding the best solution that caters to your needs, largely revolves around how the system is being used by each user. The most convenient and cheapest method of making and receiving calls is using a software based receiver known as a softphone, that only requires a headset connected to your PC to take full advantage of its functionality.  This consists of a program on each individual users computers that is registered to their own unique numerical user extension. During our initial setup, the user ID is logged into the software client using credentials provided by the VoIP system. The interface then gives users access to the full range of features from call transferring to viewing call group statistics.  A fully functional phone on your PC.

The more traditional way of setting up your VoIP system is to provide users with a physical handset that they can make calls through, just like they have always had. You can set functionality of the phones interface to provide speed dialling, call transfers, forwarding and many more options. Users still have the option to use the software client previously mentioned and the two can be synced to provide a consistent experience so that calls can be made and taken from either device.

Lastly, there is a mobile app that is available on Android and iOS. Once linked to your account, the app gives users the full call functionality that they would expect from their desk phone or software client but with the freedom of being able to take calls from anywhere with a 4G or WiFi network.


What are the options when forwarding calls to my mobile phone?

All VoIP phone systems, like many traditional phone systems, have the option of creating a forwarding from your office phone number to a number of your choice. 3CX however, our VoIP provider of choice, not only provides this functionality but also takes it a step further by allowing each individual user to create forwarding on their own individual extension, isolating the forwarding to only their extension and not the entire company.


What length of contract should I expect? My previous ISDN contract was 5 years and it cost me a small fortune.

Unlike the old style ISDN phone lines that businesses have been using for decades that are both hugely expensive, and also come with lengthy contracts, VoIP systems and 3CX is included in this, only require a 12 month contract and are significantly cheaper across the board.


How do I know how much I’ll be paying every month? And are there any setup costs?

Before a single contract is signed, an itemised quote will provide you with all the information you need split between monthly costs and one-off installation cost.  Monthly costs are broken down into the number of SIP lines you require, individual user licenses and on-going support from our helpdesk.  Extra features can be added if requested, such as the option for an IVR (Interactive Voice Response), Call reports, Voicemail to Email and Out of Hours alerts to name but a few.


I don’t really want to give up the phone number I’ve had for a long time, can I bring this with me?

Voiceflex is the company we partner with to provide our customers with SIP for their VoIP systems. To bring an existing number over to Voiceflex, a number port request for a one off fee needs to be made to your current provider (more than likely, BT) and either a temporary number provided or a forwarding activated so that no calls are lost. Once complete, ownership of this number will provide us with access to complete the setup of your new VoIP telephony system.


Our Frequently Asked Questions

Can I keep my current number?

Yes – We can port all your numbers over to us to ensure you don’t have to change anything or lose any calls​

Do I have to pay for my calls?

All calls to 01,02 and 03 numbers are free as are calls to T-Mobile, Vodafone and o2 mobile numbers​

Can I setup menu options 1 for Sales 2 for Accounts etc….


Can I get calls on my mobile and can I get my office phone to ring on my mobile?


Can I have different messages for when we are closed?


How long will it take to get the system up and running?

It depends on the number of users you need setup but typically two weeks from order to install​

Can I only call people on VoIP Systems?

No – it works with both VoIP systems and traditional BT Analogue numbers​

Can I forward calls and transfer? 


Can I take calls on my laptop instead of a phone?


What is a SIP how many do I need 

A SIP is basically an incoming line on your phone system, you can add additional SIP Lines whenever you want.  For example a Company with 50 staff we would recommend 10 incoming SIP Lines.  This allows you to have either 10 incoming calls at anyone time or 10 outgoing calls at anyone time or any combination of the two​

How fast does my internet need to be?

It will depend on how many phones you need really, a 20 user system would need at least 15Mb down and 4Mb upload, you can check your current speed here



If you have any questions or would like to discuss any topics mentioned in this article, please email


Leap IT is here to take your businesses IT to where it needs to be. We have been delivering IT Managed services throughout Birmingham, The West Midlands and across the UK for over 20 years and on behalf of more than 250 businesses. We work closely with you to really understand what your business needs so that we can make sure you always receive the best advice and achieve the best value.

With a breadth of solutions spanning IT Support, Communications, Cloud Computing and Print we see that you IT is completely covered from end to end.

This site uses cookies to offer you a better browsing experience. By browsing this website, you agree to our use of cookies.