Best way to connect mulitple Ergs for a regatta

[Less1leg]

I'd like to connect up to 20 machines for an indoor regatta. I've seen the Crash-B ergs on the internet, and a race from Europe. I've downloaded the PDF file for setting up ergs, but it leaves too much information out for the wiring diagram to connect mulitple machines. It does offer some insite about USB and WIRED, but it needs better information to connect the wiring.
I'd like to WIRE the ergs together, because there is an advantage to the wiring system from what I've read.
Has anyone a little better information? I'd like to wire 20 machines or more if possible, to a PC. Then Í'd like to use an overhead projector system to show racing in progress and race results.

What I found was too many people in and around the competitors during the indoor regatta making it difficult to not only run the regatta but for the fans wanting to watch the competiton. I'd like to expand the viewership and possibly draw local news people and media to televise the competition.
Our sport needs to expand its viewership, as well as entice new potential athletes. Indoor rowing may offer something to a new person willing to try out. We all know when we get onto the water our sport falls flat on its face because of its size of field. Media don't like our waterways because of its size, its not easy to cover a regatta as compared to a basketball game. And people become bored waiting for the race to come to them from 2000 meters away.
At least we can during the winter months offer some sort of entertainment to the crowd as too what we do on the water.

[Citroen]

What models of machines are you working with?

That's crucial.

If all machines are PM4 then it's simple to wire twenty machines - use a cat5 cable between each PM4. Last PM4 connects to the laptop with the 5m USB lead.

The PM3s used to have an expansion card the so-called "racing hat" that added the RS432 connectors and circuitry.

You're supposed to terminate RS432 with a resistive loop, but it will run OK without for 20 machines or fewer.

If machines are a mix of PM4 and PM3 the you'll need lots of USB hubs. USB has a physical limit of 5m between device and laptop or device and hub. Hubs can be daisy-chained. So to wire 20 machines using four port hubs you'll need seven hubs. That will, also, work all PM3 or all PM4 machines.

I've run ten machines using a USB setup. I've run 10 using PM4 RS432 cat5 setup.

There's loads of detail in http://www.concept2.com/us/support/soft ... BSetup.pdf
and http://www.concept2.com/us/support/soft ... eguide.pdf

It's not difficult. The biggest problem is the restricted 5m USB (the USB group claim a valid technical reason for resticting USB to 5 metres) cable length. (You may need to place the ergs in a circle with the wires in the centre and each one out like a spoke in a wheel.)

[Less1leg]

I'm going to stay with all of the same type, PM4 machines.

I don't want any compatibility problems with mix and matching when the PM4's and the PC see each other.

I also like the WIRED setup better for the Operator at the (PC).

I'm not sure what the "RS432 cat5 setup" is though. Is that a type of wire connection fitting? Does Concept2 have these available or do I have to contact an electrical hardware shop and order these things?
There are no pictures showing these connectors, in the Race Venue PDF, only PM3's with the connection.

I've got one year to get this right, tested, and waiting for our date. I don't want any surprises. If it works out I can reuse the process again at the Ontario Ergometer Rowing Championship.

[Citroen]

I'm not sure what the "RS432 cat5 setup" is though.

Cat5 is a stock standard 4*unshielded twisted pair (UTP) "ethernet" cable. The PM4 has two cat5 sockets, So you simply wire them as a daisy chain.

RS432 is the comms protocol used to make one PM4 talk to it's next door neighbour.

There's one machine connected with a USB-A to USB-B cable that's hooked up to your laptop.

It's simple to do, simple to set-up and you can get the "ethernet" cables from Radio Shack (for a dime a dozen).
http://www.radioshack.com/search/index. ... =cat5&sr=1

When I borrow racing machines from Concept2 in the United Kingdom, they give me a box of cables to connect the machines. I'd guess Scott H at C2 in Vermont would do the same.

[Less1leg]

Perfect that doesn't seem too bad.

I can get all of the materials donated from one of my sources.