Gamma Horizon Review

In this review of Gamma's Horizon phone system, we look at the company behind the service before reviewing its flagship cloud phone system. If you're here having been recommended Horizon and would like a comparative quote and opinion, please get in touch on 01202 854111 to speak to one of our independent experts.

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A brief introduction to hosted telephony

With hosted telephony, your business phone system is located in the cloud (datacentres) rather than your office. Being that it's cloud-based, you and your team can use it from anywhere as long as you have an internet connection, meaning you're no longer tied to physical equipment or telephone lines. This freedom to work from anywhere, along with a whole host of additional features, make it the perfect fit for businesses of all sizes.

Unlike traditional telephone systems, which you typically purchase as an asset and are responsible for maintenance and upgrades, a hosted telephone system is delivered as service, meaning you pay a monthly fee, and your provider takes care of the rest.

About T2k - we're brand agnostic

Ok, before we get too much further, let's point out that we are an independent business telecoms provider that delivers services to companies across the UK. For over 25 years, we have been reviewing the products and services available on the market to provide our customers with expert advice on which best suit their needs. Importantly, we are brand agnostic, meaning we aren't tied to Gamma, Horizon, 3CX or any other phone system. Yes, we sell, install and support the ones we think are best, but when you speak to us, you're not dealing with a company that only has a single solution, and because we offer a variety, we can advise you on the best fit for your requirements.

About Gamma

Gamma is a leading business VoIP provider that operates in the UK, Holland, Spain, and Germany, delivering communications services to tens of thousands of companies. Primarily they work through a network of partners who resell their services to end-users. Think of it a bit like how an IT company will often sell you Office 365; while Microsoft delivers the underlying service, it's your IT company that'll support you, and it's the same with companies like Gamma and us.

While today Gamma provides an extensive range of Unified Communications solutions to businesses, when they started back in 2002, their core services were focused more on traditional phone lines and calls. Through continual investment and advancement, they've positioned themselves as one of the best business communications companies in the UK and have built an excellent reputation.

Gamma Horizon Hosted Phone System Review
Gamma Horizon is a feature-rich hosted business phone system

Highly Rated By Our Experts
Gamma Horizon Review
9.7/10 Our Rating

Gamma Horizon is a feature-rich cloud phone system that's an excellent fit for businesses of all sizes. It offers companies an easy and inexpensive route into cloud telephony. What's more, as Gamma provides it via a network of independent telecoms companies like us, you'll benefit from a more personal approach to customer services too. While Horizon won't give you quite as much flexibility as other systems such as 3CX, it's usually the best fit for most companies. 


  • Feature-rich including:
  • Work from anywhere with soft clients and mobile apps
  • Packages from just £9.95 per user per month
  • Integrates with Microsoft Teams and Outlook
  • Generous free call bundles
  • Near unlimited virtual phone numbers
  • CRM and Outlook Integration
  • Call Centre functionality
  • Easy to use web-based admin portal


  • Less flexibility than other systems such as 3CX
  • No choice over where the system is hosted
  • Less choice of IP handsets compared to other systems

Gamma Horizon Core Features

The Horizon hosted phone system is packed full of features that businesses will find to help them work more efficiently. Perhaps the most important at the moment, with all of us continuing to work from home where we can, is the ability to work from anywhere and access all of the features it has on offer over the internet.

Here is a summarised list of the core features:

  • Account codes - assign individual calls to specific costs centres.
  • Automatic Callback - be notified when other Horizon users become available.
  • Busy Lamp Keys - know when your colleagues are free with Busy Lamp Keys.
  • Auto Attendant - route inbound calls efficiently with Auto Attendant.
  • Hunt Groups - efficiently distribute calls across your team.
  • Call Forwarding - managing incoming calls effectively.
  • Call Park - put calls on hold and pick them up on another device.
  • Call Pick Up - answer someone else's phone.
  • Call Recording - keep a record of conversations for training or monitoring purposes.
  • Call Rejection - automatically reject unwanted calls.
  • Call Waiting - make sure you're ready for the next call.
  • CLI Flexibility - you choose which number you'd like to dial out on.
  • Click to Dial - use a PC or Mac soft client to make calls.
  • Company Directory - store up to 100 contacts on speed dial.
  • Diversion Inhibitor - avoid calls being passed from pillar to post.
  • Do Not Disturb - Reject and redirect calls when you're not available.
  • Music-on-hold - play music or marketing messages to people while they wait.
  • Instant Group Call - create an ad-hoc conference call.
  • Last Number Redial - quickly repeat dial recent numbers.
  • One Number Anywhere - take business calls anywhere.
  • Sites, Groups and Departments - Adjust settings based on your company structure.

Benefits in detail

Ok, so hopefully, by this point, you know that we recommend the Horizon hosted phone system to most businesses, but let's dig further into some of the benefits of VoIP we mentioned in our summarised review a bit earlier in this post.

Work from anywhere

With the world still adjusting to the new norm of flexible working, perhaps the most significant benefit of any cloud phone system, not only Horizon, is the freedom it gives you and your team to work from anywhere. Gone are the days of needing to be where your ISDN line is to receive businesses calls, or even the need to forward calls to your mobile when you're out of the office. With the Horizon system, you can take calls anywhere you have an internet connection, on a choice of device, from desk phones and headsets to your computer or by using a mobile app. This is a massive advantage for most businesses as you no longer need to give out countless numbers, and clients can quickly get through the person or team they are looking to speak to, regardless of where they are.

No capital outlay

Unlike phone systems of old, where you would need to invest significant sums into the initial equipment purchase and setup, all costs are rolled into a monthly fee with the Gamma Horizon, hosted phone system. There isn't a large capital outlay to get started, and the ongoing costs are very affordable, with packages via T2k starting at just £9.95 per month.

Low-cost calls

Each Gamma Horizon user gets 4,000 free calls every month (2,000 to UK landlines and 2,000 to UK mobiles), and those minutes are pooled and shared across your userbase. What that means is that in most cases, your call bill will drop dramatically, and you'll likely only get bills for overseas calls or calls to premium numbers.

Unlimited phone numbers (subject to fair usage)

With Gamma Horizon, you can get almost unlimited VoIP phone numbers, be that geographic ones such as 0207, 01202, 0203 etc. or non-geographic such as 0845, 0300 etc. That means that you and your team can each have a DDI (Direct-Dial-In) number for no extra cost, and what's more, you can have numbers in cities across the UK. It may be that your head office is located in Bristol, but actually, you want to appeal to London businesses, that's not a problem, we can add London phone numbers to your system for free!

Future proof

Systems like Horizon are the future of telecoms. In 2025, ISDN lines will be switched off, so all businesses will need to move to VoIP before then. By switching, you not only get a vast range of additional benefits, but you also protect yourself from the big switch off that's around the corner.

Easy to use web portal

IT teams and administrators will enjoy the ability to manage the entire organisation's communications down to individual users' settings via an intuitive management portal.

Excellent disaster recovery

Business continuity is built into the Gamma Horizon VoIP platform. If your office loses its connection to the internet for any reason, team members can pick up their handsets and plug them in at a new internet-connected location.

Unified Communications

With Gamma Horizon, your business communications will be unified- you can make and receive calls on various devices and manage everything from your computer.

Gamma Horizon Features
Get flexibility from your phone system with Gamma Horizon

Optional extra features

In addition to the core features of Gamma Horizon, several additional optional extras allow you to expand the functionality of your system and integrate it further with the other communications tools you use in your business.

Horizon Collaborate

Horizon Collaborate is a paid-for add-on that enables the Unified Communications parts of this telephone system. With Horizon Collaborate, you get simple video conferencing, more effective remote working and reliable business continuity, all built on top of the Horizon cloud-based phone system.

Integrating Horizon with a CRM

Using Gamma Integrator, which is compatible with over 20 of the top CRM packages, your users can enjoy features such as:

  • Caller preview - display the caller's name and then match it against a record in your CRM.
  • Contact popping - Click the CRM's icon in the Phone or Preview window, and the caller's contact record will open up.
  • Activity logging - Manually or automatically create a record of the call in your CRM and give the user the option to write some notes.
  • Click to dial - Dial contacts directly from your CRM.

Horizon Desktop Client

The Horizon Desktop Client allows you to connect your office phone to your laptop or PC. You can seamlessly control your user account and manage calls effectively from wherever you are. Minimise the cost of calls when you're on the move and reduce the cost of entry by connecting existing devices to Horizon.

New features include Presence and Instant Messaging, so you can see when your colleagues are available and send a message when it's not convenient to talk.

Want to make calls from a smartphone? Download the Android and iOS apps, and your users can make and receive calls on their mobiles, just like they would in the office.

Benefits of the Horizon desktop client:

  • Reduce the initial setup cost by using the desktop client as a softphone by simply adding a headset.
  • Reduce the cost of calls when your users are moving by letting them make calls through their laptop or mobile phone.
  • Use instant messaging to communicate with your colleagues when more convenient than calling.
  • Control your user account such as setting up Call Forwarding and Do Not Disturb

Call Queuing

Horizon's Call Queuing functionality allows you to present a professional image to your customers by delivering them to groups as soon as a user becomes available.

What you can do with Horizon Call Queuing:

  • Queue up to 25 calls
  • Simultaneously deliver calls to a hunt group using Call Queue Group.
  • Set up customised messaging to deliver promotional or informational messages to people who are waiting
  • Allow callers to press a specific key to break out of the queue and leave a voicemail instead.

Receptionist Console

The Horizon Receptionist console is a low-cost way to manage call routing across many sites where a more traditional phone and sidecar solution doesn't suffice. With the Receptionist Console, you can ensure that all of your calls are answered and routed professionally and efficiently, increasing customer satisfaction and business performance.

Receptionist Console Benefits

  • Control over incoming calls to single or multiple sites
  • Access and monitor a directory of up to 800 contacts
  • Monitoring and manipulation of call queues
  • Multiple receptionists can manage single or multiple VoIP phone numbers.
  • Creation and management of multiple conference calls

Horizon Call Centre

Horizon Call Centre is Gamma's cloud-based call centre solution managed via an easy-to-use web portal. It's an extension to the Gamma Horizon hosted telephony system that allows businesses to manage their call centres easily.

Gamma Horizon Call Centre Benefits:

  • Intelligent call distribution - ensure calls are sent to the right people.
  • Quality caller experience - monitor inbound call activity
  • Flexible working - users can work from anywhere and still use the system.
  • Reporting - use real-time and historical data to make critical decisions
  • Scalable - you only pay for what you need, and the service can be scaled up or down as necessary.

Download the Gamma Horizon PDF Brochure

Lee Clarke
Sales Director

Having worked for T2k for nearly 25 years, it's fair to say that Lee is an expert when it comes to all things telephony and business communications. Overseeing the commercial side of the business, he has helped the company evolve and grow through the decades. In recent years, and with the advent of VoIP and hosted telephony, Lee has made sure that T2k is at the forefront of technological developments. With a firm interest in helping businesses navigate the world of telecoms, Lee is responsible for the majority of the content on this website.

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