Abstract:Abstract: In order to solve the problem for off-line detection difficultly of certain type vehicle-mounted switch fixed on command and control equipment, detecting Instrument has been designed by comprehensively using the computer technology, the network communication technology and the automatic testing technology. Introduces the functions, the hardware and software components about the detecting Instrument, and illustrates the performance test principles by separately taking the control-port, the ethernet-port the digital-user-port and trunk-port as the examples. The experimental and applied results show that the detection instrument has advantages in connection convenience, rapid detection speed and high automation degree etc, it is a good solution to the off-line detection problem, has met the requirements of maintenance support for forces, and can provide reference for the testing and maintenance of other command and control equipments.