Unstructured environments are challenging for conventional robots, and modular self-reconfigurable robots (MSRs) can be deployed to overcome this challenge. The goal of the current work was to develop a flexible, cost effective multi-module robot system capable of self-reconfiguration and achieving various gaits in unstructured environments. This paper discusses the communication aspects of the Modular Robot for Exploration and Discovery (ModRED) robot system from a hardware perspective. To ensure enhanced flexibility and local autonomy as well as better reconfiguration, each robot module is built with four independent degrees of freedom, and a novel docking interface provides interconnection of modules. The prototyping effort is described with emphasis on the implementation of inter-module communication. The electronic hardware layout and control system are described, and the communication system is outlined. Finally, some preliminary testing of the developed prototype is presented.