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Common Telecoms Lingo Explained

At T2K we often get asked “what is VoIP?” or “how does it work?” Although the latter has already been answered in an article before, we will touch upon the former – along with other telecoms “acronyms” or “lingo”.


What does VoIP stand for?

VoIP, which stands for “Voice over Internet Protocol” sounds very technical, but is simply describing the technology used to transmit calls through the internet. VoIP allows internet phone calls to be made without the need of traditional telephone lines. Using this allows for greater functionality of the telephone system and higher staff productivity.

What does SIP stand for?

SIP has become very popular in recent years due to allowing more incoming and outgoing calls being made whilst reducing costs significantly. Many people use SIP every day without even knowing, but what does it stand for? SIP stands for “Session Initiation Protocol”. To understand this in a simple term we will think of this as a language that VoIP devices use to communicate and understand each other.

What is an ISP/ ITSP?

ITSP stands for “Internet Telephony Service Provider”. An ITSP is more commonly referred to as a “VoIP provider”. Other names may include: Cloud VoIP Provider, Hosted Phone Provider, and Internet Phone Provider.

ISP is an internet service provider. You may also hear this term when you’re speaking with a telecoms company.

What does PBX stand for?

PBX stands for “Private Branch Exchange”. PBX systems vary massively in size and complexity based on different businesses needs and requirements. PBX systems can  be both hardware and software based but they are used to manage both incoming and outgoing calls within the business or organisation.

What does PSTN stand for?

PSTN, a type of telephone line, stands for Public Switched Telephone Network. PSTN’s make up the majority of the world circuit switched telephone networks. This type of connection allows callers from all over the world on different types of devices to communicate with each other.


We hope that this small guide has helped you understand some of the common terms that you may have come across whilst searching for a new telephone system.