when we press the “A” key on our keyboard we want to print the letter “A”. The computer takes care of all the rest.
But there are a number of ASCII codes that don’t have keys on the keyboard. The most important of these codes are the codes that have ASCII values below 32. These codes control many of SR- 10/l 5’s functions. Even though there aren’t keys for these codes, most keyboards can send these codes. It’s done by holding down the “control” key (many times marked CTRL) and si- multaneously pressing a letter key. The particular letter key that is pressed determines what code is sent. Control and A sends ASCII code 1, control and B sends ASCII code 2, and so on. Because of the way they are created, these codes are often referred to as
So there are four common ways of referring to the same set of codes: the character or name of the code, the decimal ASCII value, the hexadecimal ASCII value, and the
For example, the code that causes
line feed | - | its | name |
| |
<LF> |
| - | the | abbreviation | of its name |
ASCII | 10 | - | its decimal value |
| |
ASCII | OAH | - | its | hexadecimal | value (the H signifies hex) |
CHR$( | 10) | - | the way it’s used in BASIC | ||
- | the | way you send it from a keyboard. | |||
There’s a chart in Appendix F that shows these
The reason that we are telling you all this about ASCII codes is that people are not very consistent about how they describe ASCII codes. We are going to help you use SR- 10/l 5 with commercial software, but we don’t know what its documentation is going to call the various codes. So if you know all the different things that the codes might be called, it will be easier to figure out what it is trying to tell you.
Now, armed with the knowledge of what to look for, you can delve into the manuals of your commercial software and dig out the secrets of how to send “control codes” to your printer. When you find the method that your program uses, then you can shop through this manual to find the function that you want to use.
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