Research is being conducted on regional personal computer (PC) communication network systems to provide convenient and cost-effective PC communication services to local home users and small companies. A group communication service was proposed that offers connectionless communication to registered users via an Ethernet interface on the customers' premises. An experimental system was developed and tested. This paper presents a newly developed multiplex-port brouter that can accommodate a large number of subscribers and evaluates its performance. The system configuration and brouter architecture are also described. The configuration and function of custom LSIs that perform high-speed HDLC coding and decoding are presented. A measurement scheme that simulates multiple PC accesses is shown. The brouter performance is evaluated using PCs connected via a subscriber network system. © 1999 Scripta Technica, Electron Comm Jpn Pt 1, 82(8): 13–21, 1999