Voice Over IP (VoIP)

So what is Voice over IP (VoIP)?

Simply put, it is the transmission of voice calls over a computer data network – which means that you can use the same network infrastructure for your telephones as you do for your PC’s. VoIP works by converting the voice signals into IP packets and sending them across the IP data network. This gives you all the flexibility that you would have with a PC, i.e. you can plug your PC in anywhere on your data network and get all the relevant connections. However, like a PC, the system only works well if the entire network is set up to handle VoIP. Voice conversations are sensitive to delays and missing information and can quickly deteriorate and become unintelligible, whereas with a PC program the task just slows down slightly.

What does VoIP give me?

VoIP provides two separate solutions. The first is IP telephony whereby you have a telephone on your desk that is connected to the telephone systems via an IP data network. Secondly you have IP trunking whereby you can connect offices, homeworkers or remote sites by an IP network (Internet, VPN etc.) and route calls to them. This gives you free phone calls between remote sites as they act like an extension of your telephone system. Also it can be used to reduce costs for national and international calls as the calls can be routed along the IP network to another telephone system at the remote site, say in a different country, and this then dials out to the local telephone service provider, allowing you to reduce your international call charges.

IP Telephony

IP phones connected to your IP network allow you to place the phones almost anywhere in the office. Think about it – if all you have to do with your laptop is to plug it into a network port on your network for you to have access then you can do the same with an IP phone or a softphone on that laptop. So your phone will follow you. If you move offices then all you have to do is to unplug the phone move it to the new office ( which could be any where on your network) and plug it back in then hey presto your phone springs back into life with all your settings, extension number etc. (network setup allowing).

IP Trunking

IP trunking allows you to connect telephone systems via any IP network. So you can link offices to your telephone system and have them appear to be in one place. You can route calls between offices along the IP network and thereby making them free internal calls. National or international calls can be setup to go to different offices before “breaking out” on their telephone lines to reduce company call costs. On the other side you could have an office that specialises in a particular area of your business, e.g. product support. Calls into your local sites for product support can then be routed to the remote office with your internal network giving your customers a local number to call.

This is useful as some people can get free local calls from their telephone service provider so they will not pay for it. This is different from having an 087x number as the customer will still pay local rates. The introduction of ADSL and cable based internet access has not only improved browsing and download speeds, it has also provided a superb medium for connecting sites together using Virtual Private Networks (VPNs). Being IP based, VPNs can carry both DATA and VOICE traffic so that, with the right telephone and routing systems, small businesses can enjoy the networking benefits of IP trunking traditionally only available to large companies, at a fraction of the cost.


Session Initiation Protocol is the relatively new development in telecommunications and allows different types of multimedia calls to be made over an IP network.