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PC Specialist's Handbook ErgoPro m664-series
Edition 1 - Release 1 - March 1998 Page 5-3
Beep codes
Whenever a recoverable error occurs during Power-On Self Test (POST), the BIOS displays an error message
describing the problem. The BIOS also issues a beep code (one long tone followed by two short tones) during
POST if the video configuration fails (no card installed or faulty) or if an external ROM module does not properly
checksum to zero.
An external ROM module (e.g video BIOS) can also issue audible errors, usually consisting of one long tone
followed by a series of short tones. For more information on the beep codes issued, check the documentation
for that external device.
There are several POST routines that issue a POST Terminal Error and shut down the system if they fail.
Before shutting down the system, the terminal-error handler issues a beep code signifying the test point error,
writes the error to I/O 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).
If POST completes normally, the BIOS issues one short beep before passing control to the operating system.
List of Beep Codes:
Beeps 80h Code Description
1 B4h One short beep before boot
1-2 98h Search for option ROMs
1-2-2-3 16h BIOS ROM checksum
1-3-1-1 20h Test DRAM refresh
1-3-1-3 22h Test keyboard controller
1-3-3-1 28h Autosize DRAM
1-3-3-2 29h Initialise POST Memory Manager
1-3-3-3 2Ah Clear 512 kB base RAM
1-3-4-1 2Ch RAM failure on address line xxxx*
1-3-4-3 2Eh RAM failure on data bits xxxx* of low byte of memory
bus
1-4-1-1 30h RAM failure on data bits xxxx* of high byte of memory
bus
2-1-2-2 45h POST device initialisation
2-1-2-3 46h Check ROM copyright notice
2-2-3-1 58h Test for unexpected interrupts
2-2-4-1 5Ch Test RAM between 512 and 640 kB