Welcome to the Raymarine Technical Forum Mick,
Please note that WiFi integration with E-Series Classic MFDs, C/E-Series Widescreen MFDs, or G-Series systems will exclusively support waypoint/route synchronization conjunction with the Navionics Mobile App. It is not possible for an iPad/iPhone to access graphical sounder/plotter/radar data from these MFDs via a WiFi interface. IPad/iPhone access to graphical sounder/plotter data is limited to Raymarine's new a/c/e/gS-Series MFDs and iPad/iPhones using Raymarine's RayControl, RayView, and RayRemote mobile apps. Should a customer desire to interface their MFD via WiFi to a mobile device for purposes other than for use of the synchronization of waypoint/route data between the MFD and the Navionics Mobile app, then the solution specified within my initial response to Dave's discussion should be employed.
Raymarine determined that high data volumes within the SeaTalkhs network which is responsible for interfacing MFDs, DSM30/300G, radar scanners, and Sirius Satellite Weather/Radio receivers could and did adversely affect communications between the Navionics Mobile app and the Raymarine MFD(s). Raymarine has since removed the referenced video from its web site is seeking to have other instances removed from the Internet.
The solution to the problem would require development of custom OpenWRT router firmware to filter message traffic in multi-node SeaTalkhs networks to avoid network traffic problems. Unfortunately, the firmware update would be unique for each router in the market place and the opportunity for failure in upgrading the router firmware is relatively high, given the varying skill levels of end users and installers.
Given the information specified above and the fact that the recently introduced a/c/e/gS-Series MFDs and their integration with the Navionics Mobile App is relatively straight forward owing to their built in WiFi feature, Raymarine has decided to remove the referenced video. Upon request, Raymarine will provide firmware and instructions for configuration of the Linksys WRT54GL router. However, for the reasons specified above, Raymarine's support would be limited to providing customers with the requested files. Regarding positioning of the Router within the system, the router would be interfaced to the network switch.