Mini display port to dvi adapter

The USB is just for extra power so you can plug it into anything. I am not 100% sure a keyboard will give you the power you need since it is splitting an existing USB port, but you can try. Worse case you might have to use a different port.

 

Displayport to dvi is for the video signal (or data). It has a USB plug for the power needed to convert the signal and nothing else.

 

This is why in the adapter there is a extra USB port, so you don't waste it.

Actually, this is the dual-link dvi adapter. If you are fine with 1920x1200 resolution you can get the single-link dvi adapter, which doesn't need the extra USB for power. The dual-link is for monitors above 1920x1200 (some 27 inch screens and all 30 inch screens).

 

Reading a few reviews suggests that the USB port doesn't always work for everyone. So you might have to get a USB hub for more USB ports. The actual dvi signal corrupts sometimes with this adapter too, so a terrible apple adapter all around.

If your monitor actually comes with USB ports you can plug in the adapter to the monitor and save a port that way. Or if you have a spare phone charging brick you can use that.

Or you could get a cheap mini displayport to display port cable and use that instead.

 

Maybe I got the problem wrong, but what I did was to get a MDP to HDMI, and then get a cheap HDMI to DVI converter to stick into my monitor. Plus, this way I can plug the PC into a TV, too.

 

Unless I'm mistaken, HDMI on mac is a little crippled, and doesn't support 2560x1440 by default. From the MacBook Pro page:

• Support for 1080p resolution at up to 60Hz
• Support for 3840-by-2160 resolution at 30Hz
• Support for 4096-by-2160 resolution at 24Hz

The mini is the same so it's likely similar for all macs. Apple considers HDMI to be a tv port and supports tv resolutions.

OP should have display port support on their Dell U2713hm based on the specs so they could just get the display port cable and be done with it.