In my case I knew it was Letter Gothic, it was just a matter of the pitch, which is why I wanted a larger sample.
You can use automated OCR-like finding tools like these though, even if you don't have any idea what the typeface is.
http://www.myfonts.com/WhatTheFont/
To get a match, have a nice high res image with as many characters as possible, I usually grab a single line with character variety.