How to set up your own VoIP
In the past, your choices were fairly stark—either multiple analogue phone lines, which is what I had when I first moved into my flat, or ISDN. While the latter was very popular in parts of Europe, it never really took off in the UK or US. BT’s pricing was part of the problem, together with a lack of equipment. Nevertheless, for many years, I used a small German ISDN PBX at home. It made it simple to separate business and work calls, and thanks to the 10 number blocks BT issued as standard with ISDN2 lines, my lodger could have a number too.
Here’s how I did it.
What I wanted
I wanted to move my phone system away from old technology to VoIP. And after several years of working from home, I had some specific requirements.
Firstly, I wanted to keep my old BT phone numbers. Having had an ISDN line, with its block of 10, I used my different numbers to help me work out if someone calling was work, family, or something else. It’s not impossible to change numbers, but after running a business for 20 years, it’s a hassle making sure everyone has your new number.
I wanted the VoIP system to help make my life simpler. That means, for example, having business calls go to voicemail automatically outside office hours, so I’m not tempted to answer the work number when I should be relaxing. And with so many junk callers around, I also needed a system that could help cut down on those as much as possible.
I didn’t want to spend lots of time fiddling. Sure, I write about tech, and I enjoy a good fiddle as much as the next person. But I’d far rather be playing with a fun gadget than struggling to make my phones work.
It should also save me money. Admittedly, almost anything will save money compared to the usurious rental fees BT charges for ISDN, but it’s worth shopping around different VoIP providers and comparing their options. Some of them charge for things that others include free, and call rates or setup charges can vary considerably. And I don’t want to have to spend a fortune on either hardware or software.
Hardware and subscriptions
There are, as a quick search for VoIP will suggest, plenty of different ways to do what I want. In fact, at its simplest, if you just want a single extra phone line, there are plenty of VoIP services that will let you sign up free of charge, and pick a “landline” phone number in almost any UK dialling code. Top up with some credit, plug in a VoIP phone, and you’re ready to go. You don’t even really need to buy a VoIP phone unless you want to—just install an app on your mobile.
However, with my block of 10 numbers from my old ISDN line—I don’t use them all, but it makes more sense to keep the whole lot—I wanted something a bit more than just a bog-standard VoIP account. Instead, a SIP trunk is better. It is broadly speaking the VoIP equivalent of an ISDN line: a SIP trunk allows the Internet phone service provider (ITSP) to deliver calls to your system, and as well as the caller ID, it indicates which number has been dialed. The number of channels determines the number of simultaneous calls you can have.
SIP trunk: Gamma Telecom or Sipgate?
There are lots of providers who can give you a SIP trunk; some sell directly, others via resellers. And as well as the cost of calls, you need to check the cost of porting numbers. My choice was a two-channel trunk SIP from Gamma Telecom, via their reseller Wizards, for £15.84 per month including VAT.
The price quoted is for two channels—so effectively what I had via ISDN—including a fraud prevention service, and 2,000 minutes of calls to 01, 02 and 03 numbers per channel per month. Crucially, there are no ongoing rental charges for the numbers. Compared with BT’s basic ISDN rental, that’s a saving of almost £60 per month, with free phone calls thrown in.
A decent alternative pick is Sipgate, who’ll charge you £8.95 plus VAT for two inbound channels, and a penny a minute for UK landline calls. The first UK number is free, but you’ll pay £9.95 plus VAT for a block of 10, or £4.95 for three, which is probably a more reasonable solution for home or small office use. You don’t have to go via a reseller, and there’s a 30 day free trial, which can be a great way to experiment too. For me, though, that’s outweighed by a service that would amount to £22.68 including VAT, and not include any free minutes.
It’s also worth stressing that if you don’t want lots of numbers, a basic SIP account may do the trick, and will work with the various PBX solutions as well. It may also be a better bet if you don’t have a fixed IP address for your broadband—some SIP trunk providers, including Gamma, require your calls to originate from or terminate on a specific fixed IP address. On your internal home network, you’ll need to make sure your phone system has a fixed address too, so that any IP handsets can connect to it.
Making the switch
One of the main advantages of switching over to VoIP, besides the cost savings, is the ability to manage your calls more effectively. An auto-attendant may sound like overkill at home, but it stops all the robocalls getting through to you, because they don’t know which button to press. The more bewildered friends and family members can be added to a whitelist, ensuring they’re always put through right away.
There can be other advantages to having a proper phone system too, like the ability to make calls between extensions—useful, perhaps, if your office is in the shed, or you have a lot of floors. Or, in my case, if your entry phone is actually a phone. So, each room has a phone in it, but business calls only ring on certain phones, and only during office hours. If I’m in the back garden and someone comes to the front door, I can speak to them on a cordless handset.
Obviously, how much of this you can do will depend on your needs, and to an extent your budget, and your willingness to spend time setting everything up.
Many people will immediately suggest Asterisk as their PBX software of choice. While Asterisk is free, it can also be something of a chore to get set up from scratch.
Another popular choice is 3CX for Windows. You can run it on fairly modest hardware, and it’s both flexible and quite straightforward to set up. Best of all, for at-home purposes, there’s a free edition, which has all the features I need, but is limited to two simultaneous calls. So, if you have suitable hardware, that may put it into contention with Asterisk. The sums will be very different if you need more calls, though—commercial licences start at €350/£270 for four simultaneous calls.
There are plenty of others, too: AVM’s FritzBox range of routers will plug straight into your DSL line, and include firmware that can manage SIP accounts, and handle the analogue phone line too. They include a DECT base station and ports for analogue extensions, so you can carry on using your existing phones. The 7430 costs just £89, and supports one analogue phone, while the £195 7490 can handle two, and has 5GHz wireless. If you need a new router, either will work with both ADSL and VDSL, and give you basic VoIP functionality, including calls between internal extensions, and voicemail.
What the FritzBox won’t give you is things like sophisticated call filtering, automated assistants (voice menus), or time-of-day call routing. They’re still useful bits of kit though, not least because of those analogue ports, which save you spending money on an FXO (exchange line) or FXS (analogue phone) adaptor; Cisco’s SPA112, for instance, provides two FXS ports, for around £40. A FritzBox effectively gives you FXO, FXS, and DECT all in one.
If you’re feeling bolder, it may be possible to turn an existing router into an Asterisk-based PBX. If there’s a version of OpenWRT that’s compatible with your router, for instance, you can install that and then add Asterisk—something I experimented with on a TP Link TL-WDR3600. Again, like a FritzBox, this is more suited to basic SIP accounts than SIP trunks, and the Web interface is less feature-packed than 3CX. Another option, if you have a spare PC, is the FreePBX distro, which you can download as an ISO to set up a Linux/Asterisk system with a Web GUI. It won’t have the limitations on simultaneous calls that the free version of 3CX has, and there are paid support options available, if you need them.
A final option to consider is the Draytek Vigor BX 2000, which I’ve also been testing for this article. It’s a DSL router, capable of handling BT Infinity, and falling back to a USB 3G modem. It provides a flexible firewall, dual-band 1600Mbps 802.11ac wireless, and has a complete PBX built in, supporting two analogue lines as well as SIP trunks and up to fifty extensions, with one analogue. For £438, there’s voicemail, auto-attendants, and six gigabit Ethernet ports. On paper, it’s a complete all-in-one solution for a small- or even medium-sized office—a souped-up, much more flexible alternative to the FritzBox, in some ways.
In practise, though, I found configuration quite tricky—especially setting up SIP trunks—and it lacks some of the advanced features of 3CX, like per-extension call filtering. Nevertheless, if you’re fairly technical and want a lot of extensions, or a single-box solution for your whole network, it’s definitely worth a look.
What I chose and why
After trying the various different options described above, I’ve ended up with a system based around 3CX on an Acer Revo One running Windows 10, which cost me £150 for the Celeron version. That’s plenty of oomph for a small 3CX install, and the free edition of the software does all I need—though for some the maximum of two simultaneous calls may be limiting. It’s also a lot easier to configure than Asterisk or the Draytek Vigor BX, and as I mentioned earlier, the FritzBox wasn’t quite flexible enough to do all that I want.
The FriztBox has, however, found itself a place in my system, as a secondary device. My entry phone is connected to one of its analogue extension ports, and the phone line to its exchange port, and it talks to 3CX, providing me with analogue line fallback, and the entry phone link, plus the built in DECT base-station. The alternative would be a small VoIP adaptor, but in my case, I had a FritzBox lying around anyway. There are now VoIP entry phones available, which could connect directly to 3CX, but they start at around £200, so for now it’s easier to hook up my existing analogue one via the FritzBox.
Internally, I have a mixture of phones, including a second-hand Grandstream GXP-2000 and a Linksys SPA941, both of which can have up to four SIP accounts on them; this makes it easy to press a button and ensure that the number people see when I dial out is the one I want them to call me back on. Expect to pay from around £45 upwards for a new SIP phone, depending on how many lines you want on it, and other features. If cash is tight, use analogue extensions, and buy VoIP phones gradually. Or just use a SIP client on your mobile—3CX has dedicated clients for both iPhone and Android.
Total initial cost
Acer Revo ONE RL85 inc Windows 10—£149.00
3CX Free Edition—£0.00
SIP trunk setup and number porting—£85
Gamma Telecom two channel SIP trunk—£15.84 (including 2,000 UK mins per channel) via Wizards ISP
Once you’ve decided what you’re planning to do, getting the configuration right is important—especially the basics. If you can, it’s worth setting up your system with a new or temporary number, before porting your existing ones over. Make sure your internal phones work, and can make and receive calls—particularly if you’re replacing analogue handsets with new VoIP ones.
With my Gamma SIP trunk, there was a checklist to work through to make sure everything was behaving, such as inbound and outbound calls, caller ID, withheld ID, and so on. Only when that was all signed off was the actual number porting done. Fortunately, 3CX has a set of templates for major providers, including Gamma, which makes this relatively painless compared to working out all the settings yourself.
You should also give some thought to your “dialling plan,” the rules by which the phone system decides where to route calls. In these days of mobiles, most people are used to pre-dialling, where you enter a number and then press dial, or pick up the handset. Getting this right can make life a lot simpler, and it’s more than just “dial 9 for an outside line.”
For instance, all the phones in my flat have a two-digit extension number. So all three-digit numbers can be passed to the BT line that carries the broadband, for emergency access, and services like NHS 111. Check with your VoIP service as many do provide 112/999 service now, provided you register your address with them. If they do, you may prefer to route those calls over VoIP, with analogue fallback.
Sometimes, I work in people’s offices, and end up remembering their internal numbers. When I’m at home, my dialling rules spot a four-digit number, and add the prefix (020 7xxx) to turn that into the full DDI number. Similarly, the town I grew up in has six-digit phone numbers, so I prefix six-digit numbers with that dialling code, and eight-digit ones with 020. Anything longer than eight digits is just passed straight to the SIP trunk.
The upshot of that is that there’s no remembering to dial 9 for an outside line. For all intents and purposes, the phones behave just like a fixed landline would in London, but with quick access to family and colleagues. The only minor niggle is analogue handsets—like the entry phone—that need to add a # to the end of the number, or wait for a timeout.
It’s also worth setting up things like automated attendants to handle calls, and ring groups if you want the same number to ring on more than one extension. Sometimes a bit of lateral thinking is required to get the results you want. For instance, my ex-directory number has an automated attendant, inviting people to enter the answer to a simple maths question before they’re put through to me. It stops automated callers, but does confuse some people.
So, I created an extension with no phone attached, for whitelisting. In 3CX, you can specify the destination for an incoming number to be a particular extension, a ring group, an attendant, and so on. Calls to the XD number go to the whitelist extension. On that extension, the forwarding rules tab has an exceptions list, which can have up to 15 entries. That covers the numbers of family members, whose calls are connected directly to the VIP ring group. Other calls get the auto-attendant, and have to do the maths. You can also direct anonymous calls direct to voicemail, if you like.
Whatever sort of rules you set up, test them thoroughly. Call in to your temporary number from a mobile; check calls work in both directions. You may need to open certain ports on your firewall for incoming SIP traffic—usually the provider will be able to give you a list of which ones they need.
One of the reasons it’s important to check this before you switch a main number over to VoIP is that once you make the switch, you can’t go back easily. Porting the number from a BT line implicitly ceases the service on that line. So, moving the block of 10 numbers from my ISDN also cancelled it. If you port a number that has DSL service, the line is cut off, and with it the DSL.
So how do you keep your existing number and make the switch to VoIP? If there’s no DSL on the line, just do it. If there is DSL, you have two alternatives—and neither are convenient. You could have a new line connected for the DSL, with a different number, which costs a fair bit. Or you could have the old line reactivated after the number porting, which will give it a new number. This is cheaper, but you’ll be without broadband for a few days. You’d also be without phones, unless your VoIP provider sets up temporary call forwarding while you wait for the broadband to be restored.
Realistically, then, and especially if you’re on a tight budget, switching your main number to VoIP may be best done at the same time as moving house—and it has the advantage that unlike with BT, you can take your number outside an exchange area.
Was it worth it?
Ultimately, I’d say yes. Particularly since I started with ISDN, and the savings are considerable. But even if I’d just been cutting off one extra analogue phone line and moving it to VoIP, the flexibility for anyone who works from home is a great boon. For a relatively small outlay, I no longer get pestered by cold callers, or by out-of-hours office calls. If I’m out and about, voicemails are delivered to my mobile via e-mail, and I can use an app on my phone to dial out via the office number. Call quality has been as good as any other phone line, too.
How much you’ll save will depend on what you’re starting with—and the more complex the system you want, the more you’ll have to spend on hardware or software. It’s also important to plan carefully, especially if you’re porting a number from a line that has DSL service on it. The thought of switching to VoIP may be daunting, especially if you’re just planning on using it for home. But it’s simpler than you might think, and you really can save a fair bit of money.