Strange behaviour of Mac Mini with Dell Monitor

[isza41]

Hi All,
need some advice on an (for me) unexplicable behaviour of my Mac Mini (mid 2011) and Dell U2412M Monitor.
The basic setup, where the Monitor is connected via a direct cable from the Mini's Thunderbolt port to the Dell's Display Port, works fine.
Now I also have a Raspberry Pi computer which I would like to connect to the same Dell monitor. In order to avoid connecting and/or disconnecting cables every time I use the Raspberry Pi, I imagined that it could be possible to use a splitter in the connection and leave the Apple Mini AND the Raspberry Pi connected via the appropriate cables. In this case only the splitter has to be switched with a button accordingly. After getting the necessary cables and adapters I connected the whole stuff and switched the Apple Mini and Monitor on.
The setup works in a way, but the monitor has the colours totally changed and seems to have a higher contrast than before. Obviously the monitor is switched automatically to another profile when connected this way. Why???

The connection is the following:

Apple Mini Thunderbolt (=Mini Display) port > female HDMI > HDMI plug > Splitter > HDMI plug > Monitor Display Port plug.
Between the Apple Mini and the Splitter I couldn't find a direct cable but had to use an adapter as described above.

Any explanation of why this is happening and how it can be avoided? Thanks!

Andy

 

[Cory Cooper]

Hello and welcome.

It sounds like the culprit may be the switcher, or the fact that you are using multiple adapters to connect the Dell.

-Which model in the Dell?
-What brand/model is the switcher?
-What brand(s) are the adapters?

C

 

[isza41]

Hello Cory,
the Dell monitor is the 24" U2412M. It has no HDMI port yet but a Display Port
The cables and the Splitter are Chinese, no name products but not the cheapest. Since these cables are mostly unidirectional, it was important to find cables "from ... to", because they only work in one way. There are not too many available at all.

Andy

 

[Cory Cooper]

OK, thanks.

I would guess then it is the splitter/switcher being in the mix, if the Dell works fine directly connected to the Mac mini. You may just have to swap the cabling when you want to use the Raspberry Pi.

C

 

[isza41]

Hello Cory,
that is what I am doing now. I started the whole business of splitter & cables to avoid this but it seems I'll have to stay with switching cables. Thanks, anyway.

Andy

 

[Lufbrarunner]

I VNC to my pi, to save the trouble of cables etc.