The micro-processor controlled test box can be used to test all 15-pin N+S 24 V trailer sockets. The test box is also designed for vehicles with the latest CAN-Bus technology. The clear design enables quick trailer socket fault detection. The assignment of the socket is tested according to DIN/ISO. The earth connections (minus) are also shown. The 10 m testing cable means you can test from the comfort of the driver's seat.