https://www.techtarget.com/searchunifiedcommunications/definition/Telephony
Telephony is technology associated with interactive communication between two or more physically distant parties using the electronic transmission of data. Long associated with voice communication, telephony has evolved to also include text messaging, video calling, video conferencing, voicemail, call recording and faxing. Telephony provides an efficient and effective means of communication for individuals and businesses.
A telephonic exchange historically required the use of traditional fixed-line telephones, handheld devices containing both transmitters and receivers that connected to local exchange networks using physical wiring. Telephonic communication now uses modern computing and cellular technology, blurring the line between telephony and telecommunication. The definition of telephony and its scope have expanded accordingly.
Internet telephony lets users make calls over Internet Protocol (IP) networks at a much lower cost than using the traditional public switched telephone network (PSTN). Computer apps called softphones behave like legacy telephones but without the need for standalone devices. IP telephony software can reside on a variety of computing hosts, including PCs, laptops, smart desk phones, smartphones and tablets.
How telephony works depends on the form implemented:
Telephony provides the following benefits:
Some downsides associated with telephony, however, include the following:
There are five ways larger companies use telephony technology.
In traditional phone systems, on-premises private branch exchanges (PBXs) act as in-house switching centers, connecting calls between internal devices and routing external calls to and from the PSTN via dedicated trunk lines. Human operators managed the earliest PBX systems, but eventually, automated attendants replaced them. Operators are still employed in specific applications, like hospitals and hotels, where a personal touch and specific expertise are needed. Expensive, complex and now mostly obsolete legacy non-IP PBX systems were historically used by businesses of all sizes with great success.
Smaller businesses and remote corporate offices use so-called key systems that are designed for smaller requirements yet can be connected to larger PBX and IP PBX systems. Considering how important uninterrupted power is for PBX and IP PBX systems, a key feature called power failure transfer automatically connects specific phones to POTS lines that continue to work even in the event of power outages.
Like the traditional PBX, a VoIP or IP PBX creates a private phone network within a business but does so via the internet or a private local area network rather than dedicated voice circuits. It's often deployed on a subnet that's configured within the existing internal network specifically for IP traffic.
Because it doesn't rely on the PSTN, internet telephony can be more cost-effective than legacy technology. This depends on the system configuration; features used; special systems, such as contact centers; cost for internet access; and cost for IP device licenses.
On-premises IP PBX telephony systems consist of software running on servers, a network infrastructure, IP station sets and power systems. An on-site IP PBX typically offers more sophisticated feature sets and greater reliability than a legacy PBX system. Cloud-based VoIP service, which can be a suitable alternative, needs internet access where an IP handset is installed. On-site installations are more complex to maintain and can be more expensive per station than cloud-based systems.
Some organizations deploy a hybrid PBX model that uses both legacy and IP telephony technology for redundancy, cost savings or a staged migration to VoIP. These environments use gateways to bridge VoIP and PSTN functionality. Alternatively, a hybrid PBX approach can refer to a VoIP telephony system with both on-premises and cloud-hosted resources.
Cloud VoIP, also known as cloud telephony, is a third-party VoIP service provided by managed service providers and cloud vendors experienced in IP telephony and unified communications-as-a-service offerings. Outsourcing lets enterprises eliminate the need to provision, manage and maintain an on-site IP PBX, reduce infrastructure costs and increase scalability. Comparison of features, functionality and management controls is essential when deciding which type of telephony to use, along with costs for software licenses, network services and maintenance.
There are a range of potential individual and business use cases for telephony technologies. For example, telephony is used for text messages, voice calls, video calls, business conferences and voicemails, as well as faxes.
Other use cases of telephony systems include the following:
The word telephony comes from the Greek root word tele, which means far, and phone, which means speak. In 1876, Alexander Graham Bell patented the telephone to electronically transmit human speech, building on the success of the telegraph system. Bell's main competitor at the time, Elisha Gray, was also developing a telephone device but arrived too late at the patent office to register his patent. Bell arrived earlier and obtained the golden patent, which is considered one of the most significant patents in history.
A few days later, Bell spoke the first words ever communicated via telephone to his assistant, Thomas Watson, who was in the next room: "Mr. Watson, come here. I want to see you." The following year, he made the first long-distance phone call in history -- from Salem, Mass., to Boston -- and subsequently founded Bell Telephone Company, which would later become part of AT&T.
The earliest telephones came in pairs, with each line directly connecting just two locations. This was impractical, however, because users needed a separate wired device for each contact they wished to call. Soon, the invention of the telephone exchange enabled users to communicate with any other local party wired for service with the help of a switchboard operator. Trunk lines connected individual telephone exchanges, enabling calls to take place over increasingly significant distances.
AT&T began planning a cross-country telephone line in 1908, eventually laying 3,400 miles of copper wiring from coast to coast. Engineers used innovative loading coils and vacuum tubes to amplify electrical signals as they made their way across the country.
Thirty-nine years after filing his patent, Bell inaugurated the transcontinental telephone service with a ceremonial call from New York to San Francisco. He repeated his now-famous words: "Mr. Watson, come here. I want to see you." Watson replied from California: "It will take me five days to get there now." President Woodrow Wilson and AT&T President Theodore Vail joined them on the call.
The major milestones in the history of telephony include the following:
IP telephony and VoIP are similar technologies. Learn more about each and the differences between them.
06 Aug 2024