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EXAMPLE of OPEN Statement for Modem:

   OPEN 1,2,0,CHR$(6): REM 300 BAUD
   100 OPEN 2,2,0,CHR$(163) CHR$(112): REM 110 BAUD, ETC.

Most computers use the American Standard Code for Information Interchange, known as ASCII (pronounced ASK-KEY). This standard set of character codes is somewhat different from the codes used in the Commodore 64. When communicating with other computers, the Commodore character codes must be translated into their ASCII counterparts. A table of standard ASCII codes is included in this book in Appendix C.

Output to the modem is a fairly uncomplicated task, aside from the need for character translation. However, you must know the receiving device fairly well, especially when writing programs where your computer "talks" to another computer without human intervention. An example of this would be a terminal program that automatically types in your account number and secret password. To do this successfully, you must carefully count the number of characters and RETURN characters. Otherwise, the computer receiving the characters won't know what to do with them.


Cassette tapes have an almost unlimited capacity for data. The longer the tape, the more information it can store. However, tapes are limited in time. The more data on the tape, the longer the time it takes to find the information.

The programmer must try to minimize the time factor when working with tape storage. One common practice is to read the entire cassette data file into RAM, then process it, and then re-write all the data on the tape. This allows you to sort, edit, and examine your data. However, this limits the size of your files to the amount of available RAM.

If your data file is larger than the available RAM, it is probably time to switch to using the floppy disk. The disk can read data at any position on the disk, without needing to read through all the other data. You can write data over old data without disturbing the rest of the file. That's why the disk is used for all business applications like ledgers and mailing lists.

The PRINT# statement formats data just like the PRINT statement does. All punctuation works the same. But remember, you're not working with the screen now. The formatting must be done with the INPUT# statement constantly in mind.

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This page has been created by Sami Rautiainen.
Read the small print. Last updated May 26, 1998.