Interestingly enough, the Sharp PC-1211 (early basic programmable calculator) displays 'O' in a manner similar to what you describe. Zeros have no slash or other markings, but the 'O' has a notch in the upper right corner. See http://www.vintagecalculators.com/assets/images/SharpPC1211_1.jpg for an example. Josh -----Original Message----- From: Al Kossow Sent: Thursday, December 16, 2010 2:52 PM To: cctalk at classiccmp.org Subject: Slashing the letter O (Was: Re: Service bureaus (Was: Tek 4051 firmware listing)) There was an attempt at establishing what can roughly be described as an upside down Q for a slashed O. The only example I know of where someone used this are in line printer listings pushing this as a standard. They end up looking like misformed 8's. It does terrible things to OCR.