Nowadays regarding to necessity of precision surgery in minimally invasive surgery (MIS), particularly eye surgery for intraocular operation such as vitrecotmy, widening demand for robotically assisted surgery has shade the world of industry. In MIS, the surgeon does not need to incise the skin totally to approach the organ; so the damages and complications after surgery are reduced grossly. One of new developing fields of robots in MIS is in ophthalmology i.e. vitrectomy. While performing vitreo-retinal surgery manually, the surgeon faces various challenges. Typically, delicate micrometer range thick tissue is operated, for which steady hand movements and high precision instrument manipulation (<10µm) are required. To achieve the minimum damage to the patient through vitroretinal surgery it is required that the incision point be fixed. In many other surgeries it is necessary to rotate tools about a fixed pivot point such as any kind of MIS surgeries. Therefore, remote center of motion (RCM) mechanism are recommended for most of medical robots. ARES is a spherical RCM mechanism with it’s unique parallel mechanism and three degrees of freedom (1 DOF for the needle). In spherical mechanisms each link may be considered as an arc of great circle on a sphere. All of the mechanism links are hinged together by revolute joints and the joints axis passes through the center of the sphere. Due to orientation of joints axis the mechanism has spherical workspace and all the links have pure rotational movement about the center that induces the RCM of the mechanism. In this robot we use two dynamixel MX64R motors for the parallel arms,and one DC motor for linear movment and design a board in order to communicate MX64R protocol (RS485) with matlab s-function in RTW mode and DC motor all in 1 msec.