Int 15 Fn 43  - System - Read System Status (convertible)                  [B]

   AH = 43h

Return: AL = status bits (see #0390)

Bitfields for Convertible system status:
Bit(s) Description (Table 0390)
 7 power low
 6 external power in use
 5 standby power lost
 4 power activated by alarm
 3 internal modem powered on
 2 RS232/parallel adapter powered on
 1 reserved
 0 LCD detached