ET201D 4 door/8 door controller: Connect with sub-controller via RS485 Communication mode,KET101DE/M sub-controller has a inside Standard Wiegand 26BIT Card reader itself and can connect with a standard Wiegand 26BIT output card reader also.There are IC/ID for your option. Door lock drive signal、magnetism signal、infrared signal、fire linkage signal and exit button signal are provided by multi-door controller, Using multi-door sub-controllercan facilitate the long range wire connection 、save the material/manpower/time, keep the sub-controllers in noninterference and advance the stability of the whole System.