Under normal circumstances, how to distinguish the button switch normally open and normally closed?

The push button switch refers to the button that uses the button to push the transmission medium, so that the moving contact point and the stationary contact point are connected or dissociated, and the power circuit is switched. The button switch is a main command appliance with a simple structure and a wide range of operations. 

Q.How to judge whether the button switch is normally open and normally closed 
 
 1. It can be distinguished by the color of the wiring harborage, because if it's blue or green, it's a typically open contactpoint.However, it's a normally closed contact point, If it's red or pink. Because it has two groups, which means that it's normally open and typically closed, and also these two contact points can be touched to make or dissociate the button that can control the circuit. In order to avoid functional miscalculations, we need to flash back that different colors represent different meanings. 

2. Metal push button, Generally speaking, the upper end is normally closed, and the lower end is normally open. This is also the easiest way.

 3. The further professional system is to use a digital multimeter to distinguish it. First, acclimate to the on- off train, and also use two test pens to communicate different contact pointsrespectively.However, it means that it's a normally closed point, If a telephoning sound is heard. On the negative, it means that it's a normally open point, that is, no.