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| Chapter 20.1 - The ZX81 Printer |
| If you have got a ZX81 printer, you will have some operating instructions with it. This chapter covers the BASIC statements needed to make it work. The first two, LPRINT & LLIST, are just like PRINT and LIST, except that they use the printer instead of the television. (The L is a historical accident. When BASIC was invented it usually usually used an electronic typewriter instead of a television, so PRINT really did mean print. If you wanted messages of output you would use a very fast line printer attached to the computer, & an LPRINT statement meaning 'Line printer PRINT'.) Try this program for example. 10 LPRINT "THIS PROGRAM:",,,, 20 LLIST 30 LPRINT ,,"PRINTS OUT THE CHARACTER SET.",,, 40 FOR N=0 TO 255 50 LPRINT CHR$ N; 60 NEXT N The third statement, COPY, prints out a copy of the television screen. For instance, get a listing on the screen of the program above, & type COPY You can always stop the printer when it is running by pressing BREAK key (space). If you execute these statements without the printer attached, it should just lose all the output & carry on with the next statement. However, sometimes it might get stuck, & when this happens the break key will bring it out. Summary Statements: LPRINT, LLIST, COPY Note:None of these statements is standard BASIC, although LPRINT is used by some other computers. |
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