To find out whether your system is an 8-bit system, capable of generating all 256 ASCII codes, enter this simple test:

10 P’OR X=160 TO 254

20 L,PRINT CHR$( X> ;

30 NEXT X

If you get italic characters when you RUN this, you are using an 8-bit system.

If you have a 7-bit system, you need to understand what happens to the control codes you send. The LX-80 automatically interprets these codes the way your system sends them-as the lower half of the range. There is something you can do when you want to send the upper half (128-255): have your program convert all codes outside of the active range to their equivalent in the upper half by adding 128 to them.

The problems that are associated with 7-bit systems include:

•Limitations on width in graphics mode

•Inability to use the top pin for graphics mode

User-defined characters can’t be printed with the top eight pins (the standard position for most characters). Eight pins can’t be used in defining characters.

Remember that the best solution usually is to use an interface that can send eight bits to the printer.

Solutions for Specific Systems

The next four subsections illustrate dealing with interface puzzles on four types of computers.

Applesoft BASIC solutions

Applesoft BASIC does not use PRINT to send data to the screen and LPRINT to send data to the printer as MBASIC does. Therefore, put an PR#1 at the beginning of a program and change all instances of LPRINT to PRINT.

If one of our programs contains an INPUT statement or a PRINT statement, there will be a message that should go to the screen before anything is sent to the printer. In these programs, leave the first lines as they are and after the INPUT and/or PRINT statements, add a line that states PR#1; then change all the instances of LPRINT to PRINT and put a line that states PR#0 at the end of the program.

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