IBM PC CONVERTIBLE

Modem Presence Test
Clear
RS232_BASE
table (hex 400).
Clear
PRINTER_BASE
table (hex 408).
Turn off power to
internal modem
and serial/parallel
adapter.
Write/read hex
AAand55to
work register at
hex3FF.
To
Part 2
Figure 1-2 (Part 1 of 3). Internal Modem Presence Test
Power-On Self-Test (POST) 1-9