VoIP stands for Voice over Internet Protocol.
This translates to “Telephone calls over the internet”, however, the Internet Protocol (IP) is not only used over the internet – your office network (LAN) also uses IP for communications between servers, workstations, printers etc as well as accessing internet services such as web-sites, email etc.
So a VoIP telephone system can be used instead of a traditional telephone system (PBX) and use exactly the same wiring as your computers (whereas a traditional PBX requires its own wiring – hence the usual need to have 1 set of cabling for your computer network and a 2nd set for the telephones) AND can be setup to use your internet connection for telephone calls instead of traditional telephone lines.
So to re-iterate that point – a VoIP telephone system can be connected to traditional analogue or digital telephone lines and convert inbound calls to IP for transmission over your LAN to the telephone handset (and vice-versa, can translate outbound calls from IP to the “PSTN” land-lines);
a VoIP telephone system can be connected to your internet connection and receive calls using IP and route them across your LAN to the telephone handsets. (It’s worth noting at this point that this approach requires an external company to translate inbound PSTN calls to IP in order for your VoIP telephone system to receive the calls as IP, and vice-versa, outbound IP calls will need to be translated to PSTN for onward routing to their destination. Whilst this “SIP Gateway” provider will make a charge for the outbound calls, it will work out significantly cheaper than traditional telephone calls.)
So, there’s a significant issue to consider when deciding how to connect to the outside world:
How reliable is your internet connection?
Because if you choose to connect to the outside world using your internet connection, and the internet connection goes down for any reason, you will have no inbound or outbound calls until the internet connection is back up again. (That said, it is possible to use land-lines as a backup so that if the internet connection does go down you can make outbound calls over the land-lines and divert inbound calls to the land-line numbers – this way you will only suffer a few minutes of no calls whilst the call-routes are changed over).
Regarding telephone handsets, VoIP calls can only be made from a special type of phone known as a “SIP phone”, connected to the VoIP telephone system. However a traditional analogue telephone can be connected to a “SIP adapter”, which in-turn connects to the VoIP telephone system.
So VoIP opens-up a load of new options for telephone systems, which include:
A single in-house cabling system can be used for voice AND data;
A VoIP telephone system is usually far more flexible and scalable than a traditional PBX (i.e: it’s much easier and cheaper to add more users);
A VoIP telephone system will usually provide all the features of a very sophisticated (and expensive) PBX at a fraction of the cost;
A VoIP telephone system can be connected to traditional analogue or digital telephone-lines to provide the usual reliability of telephone calls;
A VoIP telephone system can be connected to an internet connection to reduce call costs (but can still fail-over to land-lines if required);
VoIP telephone systems are usually easier to manage;
Remote users can connect into (most) VoIP telephone systems as though in the office;
A PC-based “call-assistant” can be used to managed calls (e.g: to make a call, to answer a call, to transfer a call, to send a call to another extension, or voice-mail… and much more!);
A VoiP telephone system can be integrated into PC-based CRM software (e.g: to display lots of information about callers before answering the phone!)
Generally there’s greater call reporting facilities with VoIP telephone systems;
VoIP calls can be recorded directly onto a computer (PC or server);
For Software-based VoIP systems, in the event of a catastrophic disaster the telephone system can be quickly re-deployed onto a new computer at new premises;
Unlimited geographic and non-geographic telephone numbers can be incorporated into a VoIP telephone system (e.g: a company in Southampton could have a London-based telephone number, and an 0800 number, and 0300 etc);