Artificial acquisition and reproduction of human sensations are basic technologies of communication engineering. For example, auditory information is obtained by a microphone, and a speaker reproduces it by artificial means. Furthermore, a video camera and a television make it possible to transmit visual sensation by broadcasting. On the contrary, since tactile or haptic information is subject to the Newton's "law of action and reaction" in the real world, a device which acquire, transmit, and reproduce the information has not been established. Real-world haptics is the key technology for future haptic communication engineering. From the technical point of view, this paper proposes a unified approach of haptic communication by multilateral servo control. In controlling a multilateral servo system, coordinate transformation is an important issue. Especially, the system connection in a multilateral system affects the transmission ability of haptic information. The paper analyzes the system connection by using graph theory. The graph Laplacian in consensus problem is used for coordinate transformation, and the quarry matrix is generalized. The quarry matrix decomposes a multilateral control system into decoupled modal coordinate system. The haptic communication control is attained with respect to the modal coordinate system. The experimental results show the viability of the proposed method.