I presently use my old GT-11 as a USB GPS receiver plugged into navigation software via the USB port. I now want to capture the NMEA output hardwired directly into the NMEA input of my instruments by cutting off the large USB plug from a cable and wiring the appropriate terminals. Does anybody have the USB pinout for the NMNEA out. There are 5 wires, #1 black (presumable case/shield ground), #2 black (presumably -ve ) #3 green, #4 white and #5 red (presumably +5volt). Can anybody advise which are NMEA out. I presume #2 black is NMEA -ve. and either #3 or #4 +ve out?
Frant, please start using the return key 
sometimes.
It sounds like you are running out of USB ports. Buy a USB hub. Almost all USB devices will handle being plugged into a hub, and its usually the devices that draw a lot of power from the USB bus that have problems.
A virtual UDP port sounds like its just a network (UDP) port, that sends the NMEA data out on the network. There is probably some configuration detail with the IP address and UDP port number for this.
What needs to listen to this data? I think I need to draw a map to try and figure out what you are trying to do.
When you plug internet routers or modems into a network, they generally want to own the network and act as the default gateway (to get to the internet). If two routers are on the same network, and they have the same address, they will complain.
It sounds like you have a few ways of accessing the internet! Some WIFI routers can have an ethernet connection to connect to the internet, with a 3G dongle for connection using Telstra or someone else. I would need to know exactly what the devices are that you are using.
If you want a decent answer, you are going to have to draw me a diagram showing what connects to what and what you need to talk with.
Fixed
use
of
return
key[}:)]
However it is sticky and doesn't always work.
Have got a USB hub but abandoned using it because it wasn't 100% reliable at sea, ie often had frozen or conflicting GPS data.
Have a few ways of connecting to the internet. The satellite broadband service at $16 Mbyte needs to be absolutely sure that you don't get Windows update lurking in the background somewhere downloading hundreds of megabytes. Probably best to leave that connection as a standalone service via the Ethernet cable.
Other internet connections are via WiFi hotspots using the front panel mounted WiFi dongle.
Then there are 3G prepaid USB dongles. (Telstra, NZ telecom,Verizon and Virgin USA). Usually uninstall the driver software for all except the one in current use.
The Netgear WiFi router has provision for Ethernet cable connection to a modem for internet. How do you connect the USB 3G device?
How does the IP address system work?
Will draw a diagram of the system and post a copy. It will probably help to enlighten me to think about what I will draw.
You can get, or at least, used to be able to get, wifi routers that had an ethernet connection for an ADSL modem or whatever, and a USB slot for a 3G modem. I have one here somewhere that I bought because it was cheap and I needed to use it as an ethernet switch.
Have you got any spare PCI slots? You could install a USB card into that if you do, so that you don't need to have an external hub. Some motherboards also have additional USB ports, but you need to bring them out on an additional plate. Some motherboards have them, some don't.
If you have to use a USB hub, can you use it for the keyboard and other stuff, and dedicate a port for the each GPS?
Which IP address system? The one for the wifi router, something else, or in general?
I might have to look to see if I have some older Cisco ADSL routers around here. They can be used to router between ethernets. This can be useful to filter traffic so that you only see web traffic and email, which makes a difference for an expensive service.
