device 10 includes a housing 16 having externally accessible fiber optic or electrical connectors 18 for connecting the device 10 to the automatic door system for example a test device 10 for use with a stanley access technologies sentrex 3 u2122 automatic door system will include a first connector 17 for connecting to the sensor flex link u2122 cable 19 and a second connector 21 for connecting to the controller tb2 connector 23 the test device includes two externally visible indicators an led 20 and a four digit alphanumeric display 22 the operators for a two position selector switch 24 and a push button switch 26 extend through the housing 16 and are externally accessible a circuit board 28 mounted within the housing 16 includes an electrical circuit 30 which is electrically connected to the connectors 18 the led 20 the alphanumeric display 22 the selector switch 24 and the push button switch 26 the electrical circuit 30 includes a micro controller 32 and a memory 34 for storing test data and control programs the memory 34 may be integral with the micro controller 32 or comprise one or more separate memory units preferably the test device 10 receives its power from the automatic door system and does not require an internal power supply as a personnel and equipment safety precaution power to the automatic door system is secured until the test device 10 has been completely installed the electrical circuit 30 includes a first voltage comparator 36 which monitors the power supply voltage and lights the led 20 when the power being received by the test device.