USB Broadcaster!!!!? It won't be cheap but ...

[Sam DeathWalker]

This appears to be a usb broadcaster:

http://www.actisense.com/HTML/Products/NMEA%20Interfaces/NMEA%20Buffer%202/index.php

This is a usb to nmea 0183 converter (both in and out).

http://www.actisense.com/HTML/Products/Gateways/USB%20to%20NMEA%200183%20Gateway/index.php

Just take one of these to yur usb keypad or whatever run that to to input of the 1 to 6 (4?) buffer ... take the 6 (4?) buffer outputs to 6 more of the gateways and plug into yur computers usb ports!

I havn't looked up the prices but I dont think it will be cheap (7 converters and 1 or 2 buffers).

Its a 1 to 6 for sure but there are only 5 screwin things - obviously you can put 2 or 3 wires in each screwin thing ...

http://img182.imageshack.us/img182/7913/nbf2a150exsn0.jpg

[Steph]

It is not USB, its NMEA.
http://en.wikipedia.org/wiki/NMEA

[Tealuin]

The first link is for the NMEA buffer, but the second link is for a NMEA to USB converter.

[Sam DeathWalker]

These things have a plus and minus input (2 wire) that is differential.

http://www.actisense.com/HTML/Products/NMEA%20Interfaces/NMEA%20Buffer%202/Specifications.htm


Usb has 4 pins 2 are the differential data (I think they are also differential not sure though)


The maximum length of a standard USB cable is 5 meters (slightly more than 15 feet). The primary reason for this limit is the maximum allowed round-trip delay of about 1500 ns. If a USB device does not answer to host commands within the allowed time, the host considers the command to be lost. When USB device response time, delays from using the maximum number of hubs and delays from cables connecting the hubs, host and device are summed, the maximum delay caused by a single cable turns out to be 26 ns [7]. The USB 2.0 specification states that the cable delay must be less than 5.2 ns per meter, which means that maximum length USB cable is at least 5 meters long. However, this is also very close to the maximum possible length when using a standard copper cable.

Using USB devices over a greater length require hubs or active extension cables. Active extension cables are bus-powered hubs equipped with two maximum length standard USB cables. USB connections can be extended to 50 m over CAT5 or up to 10 km over fiber by using special USB extender products developed by various manufacturers.

Pin Name Cable colour Description
1 VCC Red +5V
2 D? White Data ?
3 D+ Green Data +
4 GND Black Ground

Im wondering if you could just cut some usb cables and use the plus data and minus data to the plus and minus outputs and inputs in the opto buffer. The ground can be common to all and you can get 5 volts from batties or usb hub with power transformer. .

Then you would not have to spend on the 7 converters.

[Wilbur]

That won't work, you can't common up the 0V between diffrent power supplies.