A man I know and liked, who also liked me, has rung me after 6 months when I thought I would never hear from him again. The last time we spoke it did not end well. Does this mean he is ready for a relationship with me now?

No it doesn't. Curiosity is the most likely scenario and in many situations it killed the cat 2!

However if he seems keen? Take it way slow.

I seriously doubt that he's ready for a relationship at the drop of a hat and based on one phone call. You give no indication of how well you knew each other previously. You simply say that you haven't spoken for 6 months and the last time you spoke it "didn't end well." Based on this, it doesn't sound like anything's brewing here.

I would not think he is ready for a relationship either. Just a phone call, seeing how you are. Don't read more into this that you can see. I agree with the other responders - take things slow, do not build anticipations or expectations into this phone call.

What did he say when he called, you haven't given a lot of info.

I have a friend that has done this for the last 14 years calling every six months or so going over ground - cut your losses!