HP dc71xx 사용자 설명서

This appendix describes the HP keyboard that is included as standard with the system unit. The 
keyboard complies with the industry-standard classification of an “enhanced keyboard” and 
includes a separate cursor control key cluster, twelve “function” keys, and enhanced 
programmability for additional functions. 

This appendix covers the following keyboard types:

■

Standard enhanced keyboard.

■

Space-Saver Windows-version keyboard featuring additional keys for specific support of the 
Windows operating system. 

■

Only one type of  keyboard is supplied with each system. Other types may be available as an 
option.

✎

This appendix discusses only the keyboard unit. The keyboard interface is a function of the 
system unit and is discussed in Chapter 5, Input/Output Interfaces.

A functional block diagram of the keystroke processing elements is shown in Figure C-1. Power 
(+5 VDC) is obtained from the system through  the PS/2-type interface. The keyboard uses a 
Z86C14 (or equivalent) microprocessor. The Z86C14 scans the key matrix drivers every 10 ms 
for pressed keys while at the same time monitoring communications with the keyboard interface 
of the system unit. When a key is pressed, a Make code is generated. A Break code is generated 
when the key is released. The Make and Break codes are collectively referred to as scan codes. 
All keys generate Make and Break codes with the exception of the Pause key, which generates a 
Make code only.