What you've been told is quite correct. It's risky buying undocumented and unverified "surplus" parts. LCD's are expensive if you buy them from distribution, particularly if you want only one.

Surplus 2x16 LCD's don't cost very much. When you're buing only one, there's generally a large penalty for the small quantity, in the form of a minimum quantity. They're almost always sold for < $10US in unit quantity by surplus vendors. It's not wise to buy them for product use, but for playing on the kitchen table, they're often adequate. The reason people are widely able to "get by" with unit quantities of these is because most of them operate in pretty much the same way. The most common controller LCD present on most LCD's is the HITACHI HD44780 or one of its clones.

If you search the www for <Character LCD> you'll find lots of information, much of which will apply to pretty nearly any character LCD with a 14-pin (either single-row or 7x2) interface connector, the likelihood that it operates in the "standard" way is very good.

Visit

http://home.iae.nl/users/pouweha/lcd/lcd.shtml

or any of the other thousands of similar reference sites for more information. There is, of course, no guarantee that this will work out, but it's very likely. Be sure to search for information on the IC's located on your particular LCD. That will help. If you write down the part numbers and search before buying that's better than doing it after the fact.

Remember, when buying undocumented and undemonstrated surplus electronics, you're gambling that they'll be what you want, and gambling, too, that they're undamaged and functional. The last time I bought surplus 16x2 LCD's I believe they cost $2 each and were packed in the original antistatic wrapping and in individual boxes. Of the 40 or so units that I bought, at the unit price of $2, every one has worked properly, so far.

Good Luck!

RE