The data dump on the previous page was made while writing an earlier version of this appendix. By comparing the column of characters at the right with the printout of hex codes, you can see that the capital A (for Appendix) in the third row, was printed as 41. You can use the table of character codes (Appendix B) to find out what character corresponds to each code.
If you look at the first character of the dump, you can see that the ESC character appears in hex as lB, and in the character column as a dot. To find the command, look at the next character, 40 hex (@), and refer to the numerical list of commands in Appendix A.
In this way you can quickly determine that prior to printing, the word processor sent seven commands to set up the printer followed by a BEL character to sound the beeper.
Command | Function | |
ESC @ | Initialize printer | |
ESC R 0 | Select USA character set | |
ESC t l | Select Epson Character Graphics | |
ESC 6 | Printable code expansion | |
DC2 | Cancel | condensed mode |
ESC P | Select | pica |
ESC p 0 | Cancel proportional | |
BEL | Sound | beeper |
If you find codes in your data dump that you did not enter in your program or codes you did not expect your application program to send, your computer may be changing the codes before sending them to the printer.
Data dump mode can be turned off by turning off the printer; it is also cancelled by an INIT signal from the computer.
IBM PC BASIC Solutions
IBM PC BASIC inserts a carriage return and line feed
Problem Solving and Maintenance |