MAC protocols are very essential to build real networks. So far, although several protocols are proposed for MAC layer, in real world systems, we always deploy heterogeneous modems. In this paper, we propose a novel wireless ad hoc MAC protocol for the master-slave heterogeneous modems, based on this kind of modems' work mode and topology structure. The protocol is of great robustness, flexibility and bandwidth utilization, improving the survival ability of ad hoc network in adverse environment. We implement this protocol in an embedded system with existing master-slave heterogeneous modems, to validate the protocol's robustness and the stability. And the related parameter values are measured. We have deployed our system in outdoors, and thereafter, we conducted several experiments on our protocol. As a result, our experimental results show that, our proposed protocol gained high performance.