The AM2-D/De is a member of the Ameritec Niagara® family of bulk call generators. The Niagara family units have push-buttons to use in controlling a front panel display, and may also be operated by sending control commands across an RS-232/Ethernet port. Ameritec offers a Microsoft Windows-based Graphical User Interface (GUI) called FeatureCall®. FeatureCall is a convenient way to program and control any of Ameritec’s Bulk Call Generators. The AM2-D/De Bulk Call Generator generates and receives large volumes of telephone traffic, generally for load and regression testing of telephone switching systems, and is designed for use on up to four PCM lines of a Central Office Exchange or PABX. Introductory paragraphs 1.1, and 1.3 through 1.6, describe concepts involved in Bulk Call Testing using the Ameritec Niagara Bulk Call Generators. Introductory topics include describing the functions of Scripts, Call Programs, Call Test Sets, and Protocols. Bulk Call Testing Bulk call testing is a method of stress testing a switch or exchange. Generally such testing is used to generate high volumes of telephone traffic while exercising many features of the switch in a ‘pre-service’ of ‘out-of-service’ environment. The purpose of the high volume is to test the ability of the switch to perform its many functions under a heavy load. Stress testing may uncover an array of problems that might not show up under light traffic or single feature test conditions, such as software bugs, misrouted calls, broken connections, incorrect setup messaging, and others, up to and including total switch failure. The easiest way to stress test a switch is to connect it to a bulk call generator. Once connected, it may be programmed to generate a large volume of calls and to exercise many switch features. For most applications, an Ameritec bulk call generator tests switches by simulating the terminal equipment that would normally be connected to the switch when it is placed in service.