User`s guide

BDOS FUNCTION 8: AUXILIARY OUTPUT STATUS
Entry Parameters:
Register C: 08H
Returned Value:
Register A: Auxiliary Output Status
The Auxiliary Output Status function returns the value OFFH in register A if the
logical auxiliary output device, AUXOUT:, is ready to accept a character for output.
If the device is not ready for output, the value OOH is returned.
3-10
BDOS Function Calls CP/M 3 Programmers Guide