can anyone explane to me what is steinberg eucon adapter. sorry if i sound like a dummy, but just wanted to no why and what it does for cubase
Looks like it is software that is required to have installed with certain Cubase versions if you want your Avid Artist and Pro Series Controller to work properly.
“The Steinberg EuCon Adapter for Cubase 6.5.0 and Nuendo 5.5.4 available here is required for the use of the AVID Artist and Pro Series Controllers.”
Regards 
They also do an app for iPad which can control cubase and it requires eucon
Since Cubase version 7 ( I believe), The EuCon Adapter is embedded within the Cubase installers, so no need to download the EuCon Adapter separately, unless you are still using an early version of Cubase, and then you would also need to be running earlier versions of EuControl. ( AVID’ s part of the solution, which depending on your version of EuControl… also requires you to have the right firmware installed in the controllers themselves).
Welcome to the party pal! 
Hope it doesn’t bother anyone that I have resurrected this old forum post. It was easter, after all.
I believe Eucon was originally owned and developed by a company called Euphonix.
It was originally a driver that allowed Euphonix own design MIDI control surfaces to connect to PCs and Macs etc. over Ethernet. They did this years before everyone else.
Avid (formerly Digidesign) could see the potential of EuCon, as well as the limitations of the current MIDI protocol, so bought Euphonix quick and then discontinued all its products. 
Then Avid, realising the way the wind was blowing, brought out lots of control surfaces which used the EuCon adaptor.
Personally, I thought it was a bit sad, as the Euphonix System 5 looked really cool
looked much more like a large format mixing console than Avids small, one size fits all control surfaces… but never mind.
Euphonix System 5-MC anyone?