Glossary of Terms

Call Tree

A Call Tree defines each step of a phone call and the corresponding actions and decisions to be performed at those steps. Call Trees is displayed visually on Active Call Center's main program window.

Global Variables

A global variable has a value that persists across Nodes in a Call Tree. They frequently store state information such as responses that have been given during a call or caller ID information.

Examples of global variables include Caller ID variables and Node variables.

Local Variables

A local variable is a variable that is only valid during the execution of a Macro at a single Node. The value of a local variable will be reset at every Node, so do not rely on this variables to store data across Nodes.

Some types of local variables are used to communicate with Active Call Center, these include: the Response Variable, Speak Variables, Record Variables, and others.

memory leak

Applications that require temporary memory request the memory from the operating sytem. When the application is done using the memory, it is supposed to tell the operating system so the operating system can use the memory for other applications. An application that fails to return the memory it had been given creates a "memory leak" - a situation in which some memory that is no longer in use is not available for future use.


A Node represents a single step in the Call Tree and stores the questions, responses, and actions that are performed at that step.

Node Variables

Active Call Center creates a global variable corresponding to every Node in a Call Tree. These variables are called "Node variables" and are used to store state information about each Node.

The names of the Node Variables are the same as the name of the Node: for example, Answer_Phone is always a Node variable since Answer_Phone is always the first Node.

program folder

The Active Call Center program files are stored in the Active Call Center program folder. The default Active Call Center program folder is C:\Program Files\Active Call Center.


Windows Telephony Application Programmer's Interface (TAPI) is a set of files and specifications for using telephony in Windows environments. Software that uses TAPI interfaces gains easy access to a variety Windows telephony devices that are TAPI compliant. Active Call Center is a Windows TAPI-based application.

In theory, any 100% TAPI compliant device will work with TAPI-based software. In reality, many TAPI devices are not 100% TAPI compliant and have minor anomalies or other "issues" that get in the way of seamless operation. The good news is that even less than 100% TAPI compliant devices can still be used with a great deal of success with Active Call Center.

Examples of TAPI compliant telephony devices are voice modems and telephony cards.

telephony card

A specialized hardware device designed to help a computer process voice calls. Telephony cards are made by manufacturers such as: Brooktrout, Natural Microsystems, Dialogic, MUSIC Telecom, and others.

Terminal Node

A Node at which the Call Tree has no path to another Node. When a phone call reaches a terminal Node in the Call Tree, the phone call will end. Call Trees can have many terminal Nodes. Any Node can be turned into a terminal Node by setting the GotoNode variable to empty ("") in the VBScript Macro of that Node.


VBScript is short for "Microsoft Visual Basic Scripting Edition". VBScript is a small, standard language designed for simple programming tasks.

VBScript is a subset of Microsoft Visual Basic and Microsoft Visual Basic for Applications, two of the most popular programming languages in the world. For more information on VBScript, refer to the chapter on VBScript Macros.

voice modem

Most modems are designed to transmit data or faxes. Certain types of modems are also capable of transmitting voice (audio) data - these modems are known as voice modems. Popular voice modem brands include 3Com, ZOOM, and CreativeLabs ModemBlaster.