What Is Telephony? Types, Benefits and How It Works

Telephony is the technology used to transmit voice, text, fax and video communications over distance. It includes traditional landlines, mobile networks, internet calling and modern business phone systems. Today, most new business telephony uses Internet Protocol (IP) to carry calls over a broadband connection.

Telephony at a glance

Meaning: technology and services that enable remote voice and multimedia communication.
Traditional telephony: landline calls carried over copper-based PSTN or ISDN networks.
Modern telephony: digital calls carried over internet connections using VoIP.
Business uses: customer calls, internal communication, video meetings, messaging and collaboration.
UK transition: the analogue PSTN network is scheduled to close by 31 January 2027.

What is telephony?

Telephony describes the systems that let people communicate across different locations. The term originally referred to telephone calls, but it now covers a wider range of services, including voicemail, conferencing, messaging, video calls and fax.

A telephony system needs a device, a network and a way to connect the people taking part. The device might be a desk phone, smartphone, computer or headset. The network may be a traditional telephone line, a mobile network or an internet connection.

How does telephony work?

All telephony captures a person’s voice, converts it into a signal and sends that signal to another device. Traditional telephone systems use electrical or digital signals over dedicated phone infrastructure. Mobile phones use radio signals to connect to nearby masts.

Internet telephony converts speech into digital data packets. These packets travel across an IP network and are reassembled into audio for the recipient. This is the principle behind Voice over Internet Protocol, usually shortened to VoIP.

What are the main types of telephony?

Traditional landline telephony

Traditional fixed-line calls use the Public Switched Telephone Network (PSTN). Older business systems may also use ISDN, which carries digital voice and data over telephone lines.

These networks served businesses for decades, but the UK is moving to digital alternatives. Openreach says the existing analogue network will be switched off by 31 January 2027. Businesses should identify any phones, alarms, payment terminals, lift lines or other services that still depend on an analogue connection.

On-premises PBX

A Private Branch Exchange, or PBX, connects extensions within an organisation and manages external calls. An on-premises PBX is physical equipment installed at the business location.

This approach can offer direct control, but it requires space, maintenance and technical expertise. Adding users or supporting multiple sites may also require additional hardware and configuration.

VoIP telephony

VoIP telephony uses an internet connection to make and receive calls. The system converts speech into digital packets, sends them across the network and reconstructs them at the other end.

Employees can use IP desk phones, computers, headsets or mobile apps. Because the service is not tied to one copper line, VoIP can support remote working, multiple locations and flexible call routing.

Hosted or cloud telephony

A hosted phone system is managed in the cloud by a communications provider rather than on equipment kept at the customer’s premises. The provider maintains the core platform, security and software updates.

Users connect through the internet, making it easier to add extensions, deploy new features and support employees in different locations. Businesses still need reliable connectivity and suitable devices.

Mobile telephony

Mobile telephony carries calls and data over cellular networks. A smartphone communicates with a nearby mast using radio signals, and the mobile network routes the call or message to its destination.

Mobile services can operate independently or integrate with a business phone platform. With a business calling app, employees can make and receive work calls using the company number while away from the office.

Internet calling and collaboration apps

Applications such as Microsoft Teams, Zoom and WhatsApp use internet telephony for voice and video calls. Many also include messaging, screen sharing and file collaboration.

Consumer calling apps are useful for informal communication, while business platforms typically add administration, number management, call queues, reporting and customer-service features.

Why do businesses use telephony?

Businesses use telephony to connect customers, employees, suppliers and partners. A well-designed system helps calls reach the right person, supports work across different locations and creates a consistent experience for callers.

Modern business telephony can combine:

Inbound and outbound voice calls
Business numbers and extensions
Auto-attendants and call queues
Voicemail and voicemail-to-email
Call forwarding, transferring and parking
Call recording and reporting
Video meetings and instant messaging
Desktop and mobile applications

What are the benefits of VoIP telephony?

Flexible working

Employees can access business calling features through compatible desk phones, computers and mobile devices. This helps office-based, hybrid and remote teams use the same numbers and call-handling processes.

Scalability

Cloud systems can usually add or remove users without installing a new physical phone line for every employee. This makes it easier to respond to growth, seasonal demand or organisational change.

Connected locations

A single system can connect different branches, workshops and home workers. Calls can be transferred between users without customers needing to dial another public number.

Useful call-management features

VoIP platforms may include auto-attendants, queues, call recording, analytics and integrations with customer-management software. Available features depend on the provider and package.

Less on-site infrastructure

Hosted telephony reduces the need to maintain a traditional PBX at the business premises. The provider manages the central platform, although customers remain responsible for suitable connectivity, devices and local network performance.

What is unified communications?

Unified communications brings several channels into one platform. Instead of using separate tools for calls, messaging and meetings, employees can access them through a connected application.

A unified communications service may combine:

Voice and video calls
Instant messaging
Presence information showing whether colleagues are available
Screen and file sharing
Voicemail
Contact-centre or customer-service tools

This approach can reduce app switching and make it easier for teams to communicate consistently across locations.

What does a business need for VoIP telephony?

The precise requirements depend on the provider and number of users, but most businesses need:

A reliable internet connection: sufficient bandwidth and stable performance for simultaneous calls.
A suitable local network: correctly configured routers, switches and Wi-Fi where wireless devices are used.
Compatible devices: IP desk phones, computers, headsets or smartphones.
A VoIP service: business numbers, licences, call plans and required features.
Continuity planning: a process for power cuts, broadband failures and emergency calling.
A migration plan: checks for alarms, door-entry systems, payment terminals or other equipment connected to legacy lines.

Is VoIP the same as telephony?

No. Telephony is the broad category covering technologies used for calls and related communication. VoIP is one type of telephony that sends calls over IP networks.

In practical business conversations, “modern telephony” often refers to VoIP or cloud phone systems because these platforms are replacing many traditional fixed-line services.

What is the difference between VoIP and a landline?

A traditional landline uses dedicated telephone infrastructure, while VoIP carries calls as data over an internet connection. VoIP is generally easier to extend across multiple locations and devices, but its performance depends on power, connectivity and network configuration.

How should a business choose a telephony system?

Start with how employees and customers communicate. Consider the number of users and locations, remote-working needs, expected call volumes, required integrations and any analogue devices that must be migrated.

Ask potential providers about call quality, support, number porting, security, service continuity, contract terms and future scalability. A good solution should fit the organisation’s working practices rather than adding unnecessary complexity.

How can Wayv help?

Wayv provides business phone systems designed around the needs of UK organisations. If you need to replace legacy lines, support flexible working or bring multiple locations together, talk to our team about your requirements.