A doorbell system and a doorbell control device are provided. The doorbell system includes a doorbell control device, a transformer, a doorbell interface device, and a chime device. The doorbell control device has a first pin, a second pin, a third pin, and a fourth pin. The doorbell control device is configured to control a conducting state between the first pin and the third pin according to a current or a voltage of the second pin. The first pin is coupled to the second pin. The transformer outputs an AC voltage to the first pin and the fourth pin of the doorbell control device. The doorbell interface device is coupled to the second pin and the fourth pin of the doorbell control device. The chime device is coupled to the third pin and the fourth pin of the doorbell control device.