Computer Telephony

Basic Principles

Computer telephony, also called computer telephony integration (CTI), is a new branch that has existed since the mid-1980s. CTI is a technology of coordinating the action of computer and telephony systems. This is an open technology that allows creating small as well as large-scale systems. The journal of 'Computer Telephony' gives the following definition of the branch: 'Computer Telephony is a technology that uses intelligible computer resources (hardware and software) to send outgoing calls and to receive incoming calls, and to manage the telephone system.'

Computer telephony today is characterized by a wealth of choices and options. It becomes a wide-distributed technology penetrating into all areas of human activity. The main reason of its popularity is that it lets companies to increase the productivity of office workers and to allow a wide range of new services to their customers.

Typical Model

The simplest computer telephony system consists of the following:

  • Voice Server
  • Agent's Workstation
  • Telephony Switch

The telephony server software manages the system by controlling interaction between agent workstations and the switch. It monitors the state of the switch's resources and controls agent activity accordingly. The telephony server also maintains call information and agent productivity data. The telephony client software supports the graphical system interface for the user and provides interaction between the agent's workstation and the telephone switch through the voice server. The telephony client can be customized to run on a variety of platforms, including Microsoft Windows, OS/2, and UNIX.

The telephone switch is the hardware component that handles all telecommunications; it receives inbound calls and transmits outbound calls.


Functioning of CT systems is based on the use of voice prompting the caller. A caller listens to a message of what options can be chosen at the moment and what action is necessary to choose a specified option. The caller makes a choice by pressing a key or a series of keys or, for instance, by a voice command. Computer telephony offers features that are not possible with stand-alone telephone equipment:

  • Intelligent call routing
  • Preview dialing
  • Predictive dialing
  • Call recording system
  • System of voice messaging
  • Interactive voice prompting


With CTI, companies can:

  • Increase productivity of office workers
  • Allow a wide range of new services to customer
  • Increase efficiency in handling calls
  • Reduce number of operators
  • Effectively use existing lines