1、电路板功能是有一出一的或功能和四个全一出一的与功能，但四个通道能选，也许会有3或者两个通道参与运算；



2、电路板越小越好；



3、输出接口最好采用插拔形式的接口，并有螺纹固定；



4、模式开关只用一个开关，分选两种模式；



5、电路板需要有电源指示灯，信号输出指示灯；若能添加输入信号指示灯最好；

-1, the circuit board is one of a function, or function and the four and one a function, but four channels to choose, there may be three or two channels participate in operation

2, circuit board as small as possible

3 had better use the plug and output interface in the form of interface, and a screw fixation

4, use only one mode switch switch, separating two modes

5, circuit board needs to have the power indicator light, signal output indicator light　If you can add input signal light is best