In most cases, a guy who is interested would have called within one week.
Now, there is a small chance that he lost your number for instance, that something got on the way or that his mind was busy with something else.
If he does not respond within a week, you can give it one more try simply to double check.
If you have his number or email, you can contact him and say something like:
"I am about to go downtown... Want to meet me there for a drink?"
Don't mention the fact that he did not call. Don't demand, question or look offended.
Simply give him another honest chance.
Sometimes, a guy won't call because he is shy or does not have the guts to take the step.
Remember, guys hate rejection.
Sometimes, they prefer simply not taking the risk rather than looking like a fool.
Give him another honest open light chance.
This will clear your questions and make sure you don't miss a chance because of a misunderstanding.