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What is Telephony?

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Question: What is Telephony?
What does the term 'telephony' mean? To what technologies is it attached nowadays?
Answer:

Telephony is a term denoting the technology that allows people to have long distance voice communication. It comes from the word ‘telephone’ which, in turn, is derived from the two greek words tele which means far and phone which means speak, hence the idea of speaking from far. The term’s scope has been broadened with the advent of the different new communication technologies. In its broadest sense, the terms encompasses phone communication, Internet calling, mobile communication, faxing, voicemail and even video conferencing. It is finally difficult to draw a clear line delimiting what is telephony and what isn’t.

The initial idea that telephony returns to is the POTS (plain old telephone service), technically called the PSTN (public-switched telephone network). This system is being fiercely challenged by and to a great extent yielding to Voice over IP (VoIP) technology, which is also commonly referred to as IP Telephony and Internet Telephony.

Voice over IP (VoIP) and Internet Telephony

These two terms are used interchangeable in most cases, but technically speaking, they are not quite the same thing. The three terms that personate one another are Voice over IP, IP Telephony and Internet Telephony. They all refer to the channeling of voice calls and voice data through IP networks, namely LANs and the Internet. This way, existing facilities and resources that are already used for data transmission are harnessed, thereby eliminating the cost of expensive line dedication as is the case with the PSTN. The main advantage that VoIP brings to users is considerable cost cutting. Calls are also often free.

This along with the numerous advantages that VoIP brings has caused the latter to become a major technological element that has gained worldwide popularity and claimed the lion’s share of the telephony market. The term Computer Telephony has emerged with the advent of softphones, which are applications installed on a computer, mimicking a phone, using VoIP services on the Internet. Computer telephony has become very popular because most people use it for free. Read more on VoIP:

VoIP Introduced
Advantages of VoIP
How You Can Save Money on Phone Calls With VoIP
Getting Started With VoIP
Top Computer-Based VoIP Services

Mobile Telephony

Who doesn’t carry telephony in their pocket nowadays? Mobile phones and handsets normally use mobile networks using the GSM (cellular) technology to allow you to make calls on the move. GSM calling is rather expensive, but VoIP has also invaded mobile phones, smartphones, pocket PCs and other handsets, allowing mobile users to make very cheap and sometimes free local and international calls. With mobile VoIP, Wi-Fi and 3G technologies allow users to make completely free calls, even to overseas contacts. Read more on mobile VoIP:

Mobile VoIP Service
Top Mobile VoIP Services and Tools

Telephony Equipment and Requirements

What is required for telephony ranges between very simple hardware to complex equipment. Let us stay on the client side (your side as a customer) so as to avoid the complexities of PBXs and servers and exchanges.

For PSTN, you only need a phone set and a wall jack. With VoIP, the main requirement a connection to either an IP network (e.g. an Ethernet or Wi-Ficonnection to a LAN), a broadband Internet connection and, in the case of mobile telephony, a wireless network connection like Wi-Fi, 3G and in some cases GSM. The equipment can then be as simple as a headset (for computer telephony). For those that want the convenience of the home phone without the computer, they need an ATA (also called a phone adapter) and a simple traditional phone. An IP phone is a special phone that includes the functionality of an ATA and many other features and therefore can work without depending on other hardware. Read more:

VoIP Hardware Devices
VoIP Bandwidth Requirements

Not Only Voice

Since many media mix up on one channel, faxing and video conferencing also fall under the telephony banner. Faxing traditionally uses the phone line and phone numbers to transmit facsimile (shortened to fax) messages. IP Faxing uses IP networks and the Internet to send and receive fax messages. This gives many advantages, but still faces certain challenges. Video conferencing works the same way as voice over IP with added real-time video. More content:

IP Faxing Introduced
Advantages of IP Faxing
IP Faxing Services
Top Video Conferencing Tools

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