Is my relay board faulty or am i missing something?

I bought an 8 channel relay board like the following

http://www.buyincoins.com/images/review/1332420113-Scheme.jpg

if i connect 12 supply to vcc and ground respectively, i have 12 v between ground and anyone of "in" pins ?
I cag get the relays to trigger if i short ground to anyone of the "in" pins.

I thought it would be the opposite? ie al the "in" pins would be 0v and i would have to supply them with +ve to get the relays to work?

If how its working is how it i suposed to work how am i supposed to use it with arduino?
I dont want to have to make a transistor circuit to short the "in" pins to ground . thats why i bought it i thought it would be plug and play so to speak.
Stumped!!!

First of all why are you using a 12vdc voltage source? As best I can see on that picture those are 5dc relay coils. Check the part number on the relays closely to determine the coil voltage. So once you do wire a 5vdc source to the board then you can control it via a digital output pin from an arduion. And yes a digital output of LOW will turn on the relay and a HIGH will turn it off, that is how the board is designed to work.

Lefty

Thanks for your reply, yeah the picture in the link is the same as my board apart from the relays on mine are 12v.

I had to take the jumper out. and put 12v supply to gnd and "jd-vcc" on relay board

Then the relay boards vcc and gnd, to arduino +5v and gnd.

And the like you said the "in" pins to digital arduino pins and write low to trigger relay.

Thanks, Corey