Table 2-1.Several computers’ print LIST commands

Command

Computer

LLIST

Epson QX-10™, IBM-PC ® , and Radio Shack TRS-80®

LIST"COM0:"

Epson HX-20 Notebook Computer™

PR#1

Apple® II

LIST

 

PR#0

 

If your listing is more than a page long (or if you didn’t start the listing at the top of a page), your printer may have printed right over the perforation. Set DIP switch 2-3 to the on position, and the printer will automatically skip over the perforation. We discuss this further in Chapter 8.

Meanwhile, printing a program LISTing is a fundamental function of the printer. Be sure you manage this before continuing (if you have trouble, consult your computer’s manual for help).

BASIC Communications

Part of the difficulty in controlling communications between computer and printer is the lack of a completely standard coding scheme. When your computer sends out a numeric code for the letter A, you naturally want your printer to interpret that code as an A. Most manufacturers of computers, printers, and software use the American Standard Code for Information Interchange (ASCII, pronounced ask-

ee)to code such frequently used characters as the letters of the alpha- bet, numerals, and keyboard symbols. Of the 256 ASCII numbers, most are codes for specific characters; some are codes for such com- puter or printer functions as sounding a beep or performing a carriage return.

The ASCII standard does not yet allow for the advanced features in today’s computers and printers. Individual manufacturers therefore adjust the codes to suit their own needs, which means that we are often faced with compatibility problems between printers and com- puters. (To compare your computer’s version of the ASCII table with the FX’s version, see your computer manual and this manual’s Appendix A.) You can usually overcome the code inconsistencies by sending control codes for advanced printer functions in care of a special ASCII code that is called an ESCape code. The next five subsections discuss these matters in more detail.

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