Thinkpads Forum

I though I have HDMI, but i Think the port that looks like is display.

I'm not sure of the diff.
But in "old" days I got HDMI.
Now it's display.

Why that? Is it because of better resolution in display?

Is there a way to get HDMI in a T420 in some way?
Expresscard?

I know I could just buy a cable hdmi to display.
But sometimes I don't have cables with me, and the other days I was a place where there was a HDMI cable and nothing else.
HDMI cable everybody have but display no one has...yet.

While HDMI is technically an older spec, they really both started becoming common on laptops around the same time. HDMI is more common on "consumer" oriented laptops, while DisplayPort tends to be found on "business" laptops. So if you had an older laptop with HDMI, it was probably a consumer multimedia style laptop.

DisplayPort is definitely a more powerful and flexible specification. It can support higher resolutions/frequencies than HDMI and daisy-chaining multiple monitors. However (and correct me if I'm wrong here), I don't think the GPU(s) in the T420 support those features, so we're effectively stuck with something similar to HDMI anyway. HDMI is obviously found on a lot more devices so in the end it may be more flexible, depending on how you think about it.

When it comes to "business" versus "consumer" specifications, Thinkpads always get the business, though, so the T420 has DisplayPort. It's technically ++DisplayPort, which means it's electrically compatible with both digital DVI and HDMI, so you can use passive adapters. You don't necessarily need a full cable either. There's ++DP to HDMI adapters on eBay that are about the size of a large thumbdrive, so that's not too inconvenient to carry around.

Thanks for the answer

That's a Displayport.
Get a (male)Displayport-to-HDMI(female) adapter, plus a male-to-male HDMI cable and you're good to go.
E.g. this adapter: http://www.ebay.com/itm/401360352244