In the Computer Science Department at Strathclyde University an Ethernet-type local network (called Strathnet) and a Cambridge Ring are being installed in parallel, to allow comparisons and experiments on the dual network. The Cambridge Ring is a 'Polynet' supplied by Logica VTS Ltd.; in this system the interfaces to our PDP-11s are UMC-Z80 based boards, operating in DMA mode, each UMC board equipped with two parts. The first port is interfaced to a Ring node, using standard Polynet hardware, whereas the second is connected to Strathnet by means of an interface board which we have designed and built to implement a simple subset of the Polynet node register set. This configuration gives an ideal dual access to the two local networks from the PDP-11 hosts in the Department, and avoids the expense of building DMA interfaces to the PDP-11 UNIBUS for Strathnet. Our paper describes the design and implementation of the hardware and software involved in the Strathnet to UMC-Z80 interface, and outlines the way in which the dual system will be used for initial experiments.