ARF-100 is a radio signal level tester, designed to work with controllers of the ABAX two-way wireless system. It is used to test the strength of radio signal received by the controller from the tester and by the tester from the controller. It helps therefore to find an optimum location for the installation of any ABAX system wireless device, which greatly facilitates designing the system in the existing premises. The tester is provided with 9 LEDs, 7 of which make up an indicator representing percentage of the radio signal strength. Another indicator is used to show the operation mode, that is, the direction from which the signal is being received). The last LED indicates the type of power supply (battery or external) of the wireless device, whose work is simulated by the tester.