Voice over IP
For the past few years I have been running a VoIP server at home and I just wanted to share my experiences with it.
My first introduction to the magical world to digital telecommunications was with a service BT ran several years ago, I can't remember the exact details but I believe it cost £5 a month and for that you got a Cisco ATA and a 055 telephone number. I used the service for over a year and was very impressed with it, the call quality was very good as was the reliability; rather than using the standard SIP protocol I seem to remember the system used Cisco's proprietary VoIP protocol, I ended up leaving this service after BT decided to move over to a SIP based system with there own hideous Router/ATA device.
I believe it was at this point that I started looking at Asterisk and Asterisk@home (now trixbox). Asterisk is an open source PBX that is controlled and run using configuration files, trixbox is the same thing but it comes packaged with a GUI, an OS and lots of other bits, it's a complete IP PBX thats easy to install and run.
trixbox connects to the outside world using either traditional telephone lines (POTS) and hardware interface cards or digital lines, these are known as trunks. For many years I used a company called VoIP Talk who provided an IAX trunk along with a few numbers, the service they offered was reliable and had good sound quality, unfortunately I had to stop using them after they decided to stop me altering the outgoing caller id.
Within the house it was running in I made each telephone its own extension, I converted some existing phones using ATA's and replaced some with VoIP phones, I ended up using Linksys hardware for most of this. This setup meant each telephone could be on a separate incoming or outgoing call at the same time and they could also call between each other. I was also able to setup ring groups, this is a list of phones that ring when one number is called, for example when someone calls me my office phone rings, as does my mobile and wireless VoIP phone.
One of the benefits of the system became obvious when I went to the Google IP conference in San Francisco, I took with me my wireless VoIP phone, this device connects to the internet using a wireless connection and then to my trixbox server using the SIP protocol, the phone allowed me to call home for free and other UK destinations at a regular rate. I also use the phone when I have wireless coverage in the UK, call costs are a lot cheaper and the quality whilst not as good as a mobile is acceptable.
One thing the system doesn't do but I would like is the ability to handle SMS messages, at the moment I have an 0871 number which people can reach me on, when someone calls this number it rings my VoIP phone, a desk phone and my mobile phone, this works brilliantly but it doesn't work with text messages. I am in the process of changing trunk provider to a company called aql as they are offering me the ability to change my outgoing caller id, they also offer SMS services via VoIP numbers so hopefully I will be able to set this up in the future.
VoIP is a system I would recommend to everyone especially businesses, it is very easy and cheap to implement and offers all the feature of expensive PBX systems. Here in the UK BT are changing there entire phone network over to VoIP so when anyone makes a call as soon as it reaches the local exchange it will enter the digital network, also when the ENUM system begins to role out call costs will reduce even further.