Coupling E6230 over HDMI on iMAC27''

Hello,

I'am new on the Dell Community.

I have a new Dell Latitude E6230 and want to use the laptop and in parallel my iMAC 27" as an external monitor.

First i check with Apple that iMAC could get video signals on his Thunderbold port. From this side the usage of iMAC as external monitor is possible.

Now i have a cable (HDMI to Thunderbold) and nothing happens.

How i can activate the HDMI port as second monitor output. The FN+F8 button toggle the output to the VGA port and not to the HDMI port.

Exist there an solution for my problem?

Thanks in advance.

Greetings Klaus