Office VOIP


This post has been a long time coming, in part because it took so long to get everything working.

It was almost 6 months ago that I decided to go down the VOIP route when my company moved to a new office. It’s a decision that I’ve questioned many times, though I think it was ultimately the right thing to do.

The background story – why I came to think this was a good idea in the first place

In my old banking job one of my duties was to work with our outsourced network providers (BT and Swisscom) on R&D projects. One of the more interesting outcomes of this was that I got roped into a ‘hot house’ at Adastral Park looking at the knotty subject of converged collaboration and communications. I got dropped into the Osmosoft team, and much fun was had by all mashing up bits of Wikis, IM, VOIP etc. One of the cool tools that I got to keep on using when the whole thing was over was Mojo, which was a consumer web application on top of BT’s (now defunct) 21CN SDK. Mojo let me initiative calls from a cloud service, and seemed to work from any telephone number to any telephone number (it could also send texts). It had its own currency – Mojits – and I would from time to time have to bother the BT guys for more (the system would charge a number of Mojits for call initiation regardless of where the end points were or how long the call was). I knocked up a basic application that let me initiate calls from my BlackBerry, which was very handy when I was roaming (as I could use it in combination with a local mobile for free calls to anywhere).

Mojo was just one of the cool tools. During the course of the Hot House we collectively came up with plans for the future of telephony, where everything would be mobile, location aware, personalised (and cheap). All the pieces of that future were there already, just unevenly distributed (and not very connected)

When BT abandoned 21CN SDK in favour of it’s newly purchased Ribbit Mojo got pushed out to pasture. Luckily JP was kind enough to arrange for me to go on the private beta of Ribbit Mobile, which offered similar capabilities (and more besides).

The original plan – Ribbit everywhere

The basic premise of Ribbit Mobile is that your mobile number is the ‘one number’ that people will get you on [1]. Through the magic of conditional call routing [2] calls to your mobile can be redirected into Ribbit’s telephony cloud. From the cloud calls can then find you elsewhere (using POTS or SIP), or the system can take a message for you, which can then be transcribed into an email/text/IM. The system also integrates with contact data, so when you get a message you can see who it’s from rather than just a telephone number [3]. For a while there was a mobile browser app at that allowed call initiation in much the same way as my old BlackBerry app on Mojo, but when the SPAMers and other bad guys started hitting the US public beta that feature got taken away.

It’s worth noting that the main application piece of Ribbit Mobile is a giant blob of Flash, and it’s fair to say that I hate using it. Luckily there’s little need to interact with the app on a frequent basis, as it can be treated as a configuration tool [4].

The piece of Ribbit that interested me for the office was it’s SIP implementation. The idea was that people could use their desk phones as better quality extensions to their mobiles (which many of my colleagues prefer to use anyway). As a backup the ‘shadow number’, which is the number that mobiles forward to in order to use Ribbit could be used as a geographic number.

Mistake #1 – buying Cisco 7940 phones

Ahead of moving to the office I bought 10 Cisco 7940G phones, and a power over ethernet switch to feed them. This turned out to be a huge mistake. If I’d done my research properly I’d have found that whilst those phones are fine with an on premise VOIP server such as Asterix [5] they don’t do a very good job of NAT traversal, which makes them pretty much useless for cloud SIP providers.

I was quite proud of myself when I got all the phones upgraded to the latest SIP firmware [download] using a TFTP server [download] on my netbook. I even managed to get the phone on my desk working (for a while) – it was getting the other 9 to work that was the problem. To cut a long story short there was no way of making these phone work reliably with Ribbit, or any other cloud SIP provider. I reluctantly gave in and bought 10 Snom 300s, which have been much more satisfactory.

The plan meets the enemy – the plan changes

Once I got the phones to work we quickly discovered some limitations of Ribbit, the main one being that we could only call UK and US numbers (a fair restriction given that we aren’t paying a Ribbit bill [yet]). So I needed something that would let us call India, France, The Netherlands and various other places that we do business. After digging around some forums, and shopping on quality rather than price [6] I settled on VoiceHost. Adding another provider also gave me a few features that I couldn’t get from Ribbit:

  • Central London 020 7… numbers (OK I admit that I’m still a bit snobby about 020 3… numbers)
  • Call groups
  • Transfer between extensions
  • Fax to email
  • Conference calls [7]

I hope that one day there will be a Ribbit SME or Ribbit Office solution that gives me the best of both worlds from one provider (and then I just need to cross my fingers that the numbers will be portable).

Mistake #2 – BT business broadband

I really wanted a fibre connection for the new office, but that was going to cost lots and take ages. I’ve already written about this, but the short version is… I was fooled into thinking that we could get ADSL2, which would have been just about good enough, but in the City you can only get bad old ADSL, with atrocious contention. ADSL in the City isn’t enough to run more than about 1 VOIP call, which isn’t really good enough in an office with 10 desks and 2 meeting rooms. This was eventually resolved by getting an EFM connection.

Steady state

People are used to phones just working, and we’re now at a state where they pretty much do. I can’t say that I’m happy with the cost – when you add up the EFM and the monthly VOIP bill it’s a fair bit more than I’d guess we’d be paying if I’d gone down the traditional POTS/ISDN/PABX route. US centric stories online tell of all you can eat SIP trunk tariffs and cheap good quality broadband, which are things that are hard to come by in the UK – don’t get me started about BT and regulatory capture.


I now have a ‘work’ line in my home office that integrates seamlessly into both Ribbit and Voicehost, and after some recent tweaks by the Ribbit guys it’s been rock solid reliable. I’m not the only one – 5 of my colleagues have the same capability. It goes beyond the home office too – a colleague has spent much of August on ‘staycation’ in a cottage that has lousy cell signal but good enough broadband. He’s been able to have an ‘office’ extension there for when he needs it – without crazy costs or engineering bother.


Computer Telephony Integration (CTI)

I can make my phone dial by logging into its web interface and pasting a number into a form, but I want to be able to just click on numbers in my CRM and contact management systems and have them dial. CTI is a basic capability of this type of setup, but the integration to make it work isn’t easy enough (yet).

Location based dynamic routing

I tend not to fiddle much with the routing of my numbers to my devices, and I expect that this annoys my work colleagues when my phone rings when I’m not there (I had to buy a new phone for the home office with a second line and a distinct ringer to reduce similar annoyance to my wife). This is a solvable problem in principle, as my smartphone knows where I am, and so I should be able to run an app on it that updates my telephone routing in the cloud.


Going VOIP for the office has cost more than expected and has yet to deliver the full breadth of functionality that could be expected of it. For the extra money we have got extra functionality (and a reliable data network) and the promise of more jam tomorrow.

[1] It also has a concept of ‘purpose numbers’, though these aren’t implemented fully in the UK yet, which could be regular geographic telephone numbers.

[2] A magic that’s missing from some PAYG tariffs

[3] Though annoyingly they still haven’t implemented my feature request to set ‘reply to’ headers so that you can send an email back to a voicemail transcription without messing around with the To: field.

[4] Though it does have lots of features like a softphone and the ability to listen to messages and read transcriptions

[5] Or their native Cisco Unified Communications Manager (CallManager)

[6] Shopping on price would have probably taken me to Localphone, and one day I might find the time to set up something that does least cost routing etc.

[7] That people dial into rather than the sort where you dial out to multiple extensions (which Ribbit can do)

6 Responses to “Office VOIP”

  1. 1 Joe Maissel

    Do you use a software client for your redirected to SIP calls (the Flash thing?)? Or, do you take the SNOM with you?

    • 2 Chris Swan

      I don’t use a softphone, but I also don’t lug around the SNOM. Call routing probably deserves its own post… coming up.

  2. 3 Mharburn

    Sorry to bump an old post but is the EFM still working out? I’m still hitty miss on EFM vs LL when it all goes wrong for clients. A pm would be cool.

    • EFM worked fine technically, but I always felt it was poor value for money versus some of the other options (WiMax would get more bandwidth for the same money, and Fibre Optic would get a lot more bandwidth for about twice the cost).

  3. 5 Mharburn

    So that leaves the question of reliability though, do you think if it went wrong BTO would care very much? Up in the north of england our choices for wimax are limited to specific areas and most conectivty is flaky or expensive.

    • We only once ever had an issue with the EFM connection, which turned out to be a port duplex mismatch issue. I was impressed (and happily surprised) with how swiftly and professionally it was dealt with – it seems that the service premium does at least pay for a decent support facility.

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