The evaluation device type 656 is used to record and evaluate current signals, 4...20 mA, from vibration monitoring in two-wire technology. The switching threshold and delay time can be set on the evaluation device. If the signal exceeds (type A) or falls below (type B) the switching threshold and the delay time has expired, this is signaled at the outputs by means of LEDs and relays. Cable breaks and a lack of power supply are also signaled. These signals can then be used to generate an alarm.