Real-time robot controls in remote surgeries require real-time communication also for multi-hop networks. In this paper the prototype of a new Synchronous TDMA (STDMA) Switching Hub to realize real-time communication in this application field is presented. In general transmission time of a switching hub varies depending on network load and traffic. Even in case real-time communication networks are used for all subnets, the switch delay time is accumulated with each hop. The proposed system shall provide real-time communication within multi-hop networks containing subnets of all levels of complexity. To stabilize the transmission time, a new protocol for a resource reservation systems is proposed. Based on the results of extensive performance tests in a multi-hop environment the proposed STDMA switching hub is able to reduce delay time to 10μs with 3.2μs jitter for each hop.