assign the current value on the display line to a given variable, which could then be used in a program. Combined with a defined key, this allowed very quick custom operation. The program interpreter on the models did not provide human-readable error information. Errors encountered either in program execution or calculation evaluation would be returned as one of 9 error codes, usually indicated by replacing the display with text such as "ERROR 4". On the PC-7 model the list of error codes was printed above the text keypad, and was included on the case of the PC-8, but with other models users not familiar with the meaning of each code would have to refer to the manual. Like other characteristics of this line, the meanings of the error codes were not necessarily equivalent from model to model. Undocumented commands The PC-8 had a couple of commands that were not listed in the manual, but nonetheless were recognized by BASIC and usable. and - the highest memory location is 2047, and it is possible to modify the BASIC program in RAM directly with , as well as access a certain memory location (37, possibly?) that controls the DEG/RAD/GRAD spots on the LCD. With judicious POKEs into the BASIC program text area more characters in the PC-8 character set can be discovered, including a `tilde` which also seems to function as a bizarre command. Some blank characters when 'ed will display additional symbols on the printer if one is attached. - seems to be some type of test mode for the display. Will show a couple of patterns on the LCD and then appear to lock up. - seems to be some type of test mode related to the optional Printer Interface Also, SHIFT-6 on the PC-8 will display a Yen symbol. See also Sharp PC-1211 Sharp PC-1500 Sharp pocket computer character sets Casio calculator character sets References External links Tandy Pocket Computers at the Pocket Museum Floodgap Retrobits Tandy! Pocket! Mania Sharp PC-1500 computer (TRS-80 PC-2) resource page - much documentation. All and more about the Sharp PC-1500 computer (TRS-80 PC-2) Pocket computers