Computer telephony is a common name for any technology that allows interactions on a telephone and a computer to be integrated or coordinated. Computer telephony allows you to combine voice transmission with digital data transmission, as well as provide call tracking and management according to any scenario (voice, email, web interface, fax, etc.).


History of the analysed term

Computer telephony integration began in the 1970’s with the advent of the automatic call distributor (ACD). ACDs were used to distribute incoming calls to select agents based on certain call parameters like the number dialled or the time of the call.

In addition to distributing calls, organisations also wanted to improve the efficiency of call centre agents by matching incoming phone calls with relevant information stored in their customer databases. computer telephony allowed data collected by the phone systems, such as the caller ID or automatic number identification (ANI), to be used to query databases – such as the CRM – and populate that data on the screen of the customer services team.

Initially, computer telephony was implemented by installing software on a physical computer or device like the company private branch exchange (PBX).

At its inception, there were many different standards of computer telephony across the industry, with each PBX / ACD vendor using a slightly different variation. These standards included CSTA, JTAPI, TSAPI and TAPI to name just a few. Another words, it was a complex market with many individual technologies requiring custom integrations to link phone systems and all the rich customer data in CRMs.

In order to understand the evolution of computer telephony, it is important to remember that, at first, enterprise software, like CRM systems, as well as telephony equipment and software, were all installed on-premise, at an organisation’s office or data centre.

This began to change with the emergence of software as a service (SaaS), where companies could deploy and manage enterprise software, like Salesforce, in the cloud. Following suit, a new breed of call centre software companies began to offer fully integrated telephony solutions through the cloud. Cloud call centre software included ACD, interactive voice response (IVR), computer telephony, call routing and CRM integration, which providers could easily deploy and manage.

However, in order for a SaaS CRM system like Salesforce to work with a cloud call centre solution, users had to install a  computer telephony adapter program. A computer telephony adapter is a light-weight software program that controls the appearance and behaviour of a softphone and allows agents to place calls, answer calls and transmit audio, using features of the physical (on-premise) computer.

This presented a problem – especially for a company like Salesforce whose slogan is “No Software”. It forced application developers to use a  computer telephony adapter toolkit, which required software to be installed. That conflicted with the overall goal of removing on-premise software. Software applications caused organisations to face security issues from applications like Java, which could provide a point of vulnerability. It also made management more difficult as software had to be installed and upgraded on each agent’s desktop computer.

That led Salesforce to introduce Open computer telephony.


Common functions

By application type:

Computer telephony applications tend to run on either a user’s desktop, or an unattended server.

Common desktop functions provided by computer telephony applications

  • Screen popping – call information display (caller’s number (ANI), number dialed (DNIS), and Screen pop on answer, with or without using calling line data. Generally this is used to search a business application for the caller’s details.
  • Dialing – automatic dialing and computer-controlled dialing (power dial, preview dial, and predictive dial).
  • Phone control – Includes call control (answer, hang up, hold, conference, etc.) and feature control (DND, call forwarding, etc.).
  • Transfers – Coordinated phone and data transfers between two parties (i.e., pass on the Screen pop with the call.).
  • Call center – allows users to log in as a call center agent and control their agent state (Ready, Busy, Not ready, Break, etc.).

Common server functions provided by computer telephony applications

  • Call routing – The automatic routing of calls to a new destination based on criteria normally involving a database lookup of the caller’s number (ANI) or number dialed (DNIS).
  • Advanced call reporting functions – Using the detailed data that comes from computer telephony to provide better-than-normal call reporting.
  • Voice recording integration – using data from computer telephony to enrich the data stored against recorded calls.

By connection type

Computer-phone connections can be split into two categories:

  • First-party call control

Operates as if there is a direct connection between the user’s computer and the phone set. Examples are a modem or a phone plugged directly into the computer. Typically, only the computer associated with the phone can control it by sending commands directly to the phone and thus this type of connection is suitable for desktop applications only. The computer can generally control all the functions of the phone at the computer user’s discretion.

  • Third-party call control

Interactions between arbitrary numbers of computers and telephones are made through and coordinated by a dedicated telephony server. Consequently, the server governs which information and functions are available to a user. The user’s computer generally connects to the telephony server over the local network.


Area of usage for the term

With Computer Telephony, tasks can be carried out from any computer, thereby benefiting smaller companies that lack the resources to maintain costly communications infrastructures. This technology is often used in call centers, since they field a large volume of calls and continually seek to enhance productivity.