VoIP – Voice over Internet Protocol. This is an umbrella term for any form of voice communications where voice is carried over any IP network. This could be over a private data network (eg your office network) or over the Internet.
IP PBX – A PBX (Private Branch Exchange – or put simply a phone system) that uses IP rather than dedicated cabling or the PSTN phone network (‘normal’ phone cabling and systems eg BT)
Hosted VoIP/IP PBX – Voice traffic uses the Internet (Broadband), PBX functionality is provided by a 3rd party
SIP trunks – Use your broadband connection to make calls, often reducing the cost. Can be used in conjunction with an traditional premise based PBX (extra card may be required) for the “best of both worlds” – high quality calls for every day use while using trunks to save on line rental and call charges.
ISDN lines are due for retirement in 2025!!