CRESTRON
Appendix A: AT Scan Code The PC interface is designed so the system software has maximum flexibility in
defining certain keyboard operations. This is accomplished by having the keyboard
return scan codes rather than ASCII codes. Each key generates a “make” scan code
when pressed and a “break” scan code when released. The computer system
interprets the scan codes to determine what operation it is to perform.
The illustration of the PC keyboard, shown below, in conjunction with the AT scan
code table, on the following page, provides the “make” and “break” scan codes.
Simply identify the specific key on the keyboard illustration. Notice that each key
has a “find #” printed in the lower right corner. Locate the “find #” in the AT scan
code table to determine the “make” and “break” scan codes. For example, from the
keyboard illustration, notice that the “S” key has an “find #” of “32”. From the AT
scan code table, notice that “find #” 32 has a “make” scan code of “\x1B” and a
“break” scan code of “\xF0\x1B”. Although typical “break” scan code is simply the
“make” code preceded by hex F0, there are exceptions. Therefore, refer to the
enclosed table for accurate scan codes.
PC Keyboard with Find #s
Operations Guide - DOC. 5700A Wireless Mouse • 23