Nuvi 350 Dock Connection Single Cable Mods.
- Just wanted to post (to share and yes brag) that I just finished my Nuvi 350 Modding and now my Nuvi 350 works completely normal when not docked (with the exception of still being in FMI mode) and then when docked it switches over to the 8.2K id signal, gets its power and talks to the OT2 via the dock without any plugs, dongles or switches via the single dock connector and USB cable. The T2 connects to my Yaesu with a single cable, and everything's working great!
I have to start work now on documenting it on a site, but knowing how I procrastinate on documentation I wanted to include a few pics here if anyone else is considering modding theirs.
The toughest part was detecting when it was docked, and while looking at locations to mount switches etc... it hit me, the bottom of the cradle connector has a lip that reaches around the bottom of the 350 and holds it tight. This is also the only internal space where a switch is easy to mount. I drilled a small hole into the Nuvi inside this recess, and mounted a small PB inside the Nuvi with a 8.2K resistor tied between Gnd, and the USBID test point on the board. when you dock the Nuvi the switch closes and it kicks into FMI mode, connections from the 2 USB/Serial test points on the board are wired to the extra 2 connections for the dock connector, and inside the dock connector these 2 middle pads are jumpered over to the USB connector, then in the FMI Cable I rewired the "blob" to connect the red wire over to the Nuvi side for power, which ties to pin 4 on the Nuvi serial port. I haven't noticed any heating issues of the OT2 from drawing the charge power from the OT2's 5V regulator yet, but I'll be changing the regulator over to a 5V switching power supply soon just to beef it up. I've now got a nice simple 1 cable solution that will clean everything up nicely.
Pictures are posted in the pictures section under VE6RKY Nuvi Mods.