Acer 1800 - Manual (Page 67)

59 Chapter 4
Terminal POST Errors
There are several POST routines that require success to finish POST. If they fail, they issue a POST
Terminal Error and shut down the system. Before shutting down the system, the error handler issues
a beep code signifying the test point error, writes the error to port 80h, attempts to initialize the video,
and writes the error in the upper left corner of the screen (using both mono and color adapters).
The routine derives the beep code from the test point error as follows:
1. The 8-bit error code is broken down to four 2-bit groups.
2. Each group is made one -based ( 1 through 4) by adding 1.
3. Short beeps are generated for the number in each group.
Example:
Testpoint 16h=00 01 01 10=1-2-2-3 beeps