IP Telephony Basics


Today’s telephone systems still do what they have always done. Answering, dialling, transferring and holding calls are fundamental features we could not live without. However, the way today’s systems interconnect with other systems and technologies is the really interesting part. Many everyday tasks have been automated and telephones systems now make a valuable contribution to increasing staff productivity and lowering operational costs.

In and around the year 2000, voice traffic took a rather big turn in terms of transmission method. What was traditionally known as ‘circuit switching’ where callers used a point-to-point path to make a voice call, something known as Voice over IP became reality and ‘packet switching’ became the new standard to follow.

Developments in data networking, wide area networking and the internet quality now allows calls to be sent across the internet connections worldwide at such a pace that quality issues are diminishing.

Most telephone systems suppliers now offer IP-Enabled or Pure IP solutions. IP enabled refers to traditional digital telephone systems that have been adapted to support voice over IP technology.

A Pure IP telephone system is based on pure IP switching methods and will offer better scalability and more integration with 3rd party systems and softwares.

In its most basic form VoIP enables broadband users to make calls over the internet for FREE. However, if you have ever used SKYPE or MSN Messenger you will know that the other person must have the same software and be subscribed to the same service for this to work.

The main disadvantage of these ‘free’ services is that each user must be online and signed up with the same service. In order to make a ‘normal’ call to someone on a landline or mobile you have to break out from the VoIP network. This is where the call becomes chargeable.

Broadband in the UK started at 512k, then the speed went to 2 mb/s, now its up to 24 mb/s. A direct result of the internet speeding up is the level of service provided by Voice over IP providers gets better.

Recently we have a new player in the world of Voice over IP known as SIP. Session Initiation Protocol is a new signaling method which allows for better quality of voice over internet. SIP supports Quality of Service (QOS) which essentially guarantees the quality of voice over data networks.

As mentioned earlier in this guide, VoIP providers are becoming more common place and will continue to drive IP trunk services to SME businesses. However, for now lets explore the other key advantages of IP telephony.

Multi-Site Networking with VoIP

By enabling each office location with a VoIP based phone system you can easily link each location together using the internet. Once linked together internal dialing across each location is seamless and free of charge.

Key Benefits:

  • It saves the cost of using BT to make an inter-branch call
  • Unified extension numbering plan
  • Centralised management and application sharing
  • Overflow/transfer calls from site to site

In summary this means that all inter-office calls are free and every member of staff can reach all remote staff simply by dialling their internal 3 or 4 digit extension number. Small offices and remote workers e.g. from home can also be integrated as part of a VoIP network.

Some standard features of VoIP telephone systems include any user in any location viewing extension status, using voice mail, call recording and viewing their call history from anywhere.

Having a VoIP network in place for internal voice calls is great, but its not all about cheaper calls. Take a look below at some cost benefits of a phone system integrated to your I.T infrastructure:

  • Adds, moves and changes become less because you can nominate a member of staff to take control of everyday changes to the telephone system
  • Easy to use Windows based interface for programming changes
  • No additional cabling when taking on new office locations
  • Easy integration with your existing applications based on open standards

Something to consider when choosing IP Telephony is the state of your current network infrastructure. Is it ready for VoIP?