How many axes of Dobot Arm V1.0 ? Where do they fall on separately?

Dobot Arm V1.0 is a four-axis robot arm with parallel interconnection. Joint1, 2, 3, 4, Joint1-Joint3 are corresponding to the base, forearm and rear arm, respectively, using motor stepper. And Joint4 is for the rotation of end holders (gripper and suction cap), using servo instead.