ISDN is Out, SIP is In.

There are over 3.2 million ISDN channels in use in the UK right now. By 2025 that number will be zero! BT has finally given the word and set firm dates to switch off the service. So, you have four years to migrate yourself away from ISDN and onto SIP. That may sound like a long time, but it really is not. Every business relies on and trades on its telephony. It really is time to think about upgrading that legacy telephone switch that’s in a cupboard somewhere. It has probably been working for years and you’ve never given it a thought because it just works. 

IP PBX or Hosted Solution?

Your choices for a new system will seem fairly simple. You could install a new IP PBX in the same cupboard as the existing unit or you could go for a cloud-hosted product. It’s a matter of preference really. As essentially the users really won’t know much different. What is important, however, is your existing network infrastructure. If you think you can just remove the old system, replace the handsets and expect to get the same performance, then think again. 

Network Infrastructure is Key.

Your new solution will only be as good as the weakest link. That weak link could be any one of, or a combination of the following:

A single poor DSL connection, your existing CAT5 infrastructure, your network switches, consumer-grade routers/firewalls which were not designed with SIP in mind. This is not an exhaustive list by any means. It is merely meant to highlight the challenges of successfully implementing a new telephony system. 

Engage the Users.

It makes no difference if you’re going to hang 5 or 500 handsets off the new system, if your underlying infrastructure is not rock solid and well designed then not only will you have problems, you’ll spend a lot of time and money getting to the bottom of the issues. Most importantly if you don’t implement the migration to the new system correctly out of the gate, then the users will very quickly lose confidence in it. That negative perception will create a lot of heartache for support staff for a very long time.

Before you rush in and pick a hosted VoIP provider or a shiny new IP PBX then you’ll want to tick a few things off your “SIP system project list”: 


CAT6 cabling. Terminated to good quality CAT6 patch panels, installed, tested and documented by a competent network cabler (read, not your local electrician). This should be connected via CAT6 patch cables to a quality, managed network switches. Ideally, you’ll want to either keep the voice and telephone as separate physical networks or implement a well thought out VLAN infrastructure. 

Connectivity for VoIP.

Internet connectivity. Connection speeds seem to be getting faster and faster and cheaper and cheaper. Whilst that may not be a bad thing, for a good VoIP experience, you’ll want a quality, stable connection to a business ISP that has it’s own core infrastructure and knows how to get the best out of VoIP. With VoIP, it’s not all about download speed. You are going to need good upload speeds too. Although it’s by no means a hard and fast figure, if you work on 100Kb of bandwidth per voice call it will give you a good idea of the sort of connection you’ll need. If you plan to have voice and data on the same connection then your ISP should support QOS (quality of service). This will allow you to reserve a certain amount of the overall bandwidth for your voice traffic. 

WiFi Woes.

Wifi. If at all possible try and avoid having your voice traffic going over WiFi use your nice shiny CAT6 copper. If you intend to have any number of voice clients using WiFi then get the devices into the 5GHz spectrum and out of the 2.4GHz space. Set up separate SSID for employee devices and conduct a thorough WiFi survey to ensure the wireless environment is “clean” and has no blackspots.

Only once you’ve got a good solid network infrastructure in-place are you then ready to migrate to a new hosted SIP system or install an IP PBX.  

We're Here To Help!

6 + 1 =


Oak House B, Ransom Wood Business Park, Mansfield, NG21 0HJ


M-F: 9am - 6pm
S-S: Closed