FBDFh - MHT RS232 8253 timer 0-2 control
Clock Input is '''unknown''', Clock output goes to a [[8251 USART chip]],
Clock Output may be further divided by 1, 16, or 64 in the USART chip
=== Schneiderware V/24 Interface ===
Used by [[Schneiderware V/24 Interface]], mapped to ports:
F9ECh (or F9E8h) Schneiderware V/24 8253 chip Timer 0 (TX clock)
F9EDh (or F9E9h) Schneiderware V/24 8253 chip Timer 1 (RX clock)
F9EEh (or F9EAh) Schneiderware V/24 8253 chip Timer 2 (unused)
F9EFh (or F9EBh) Schneiderware V/24 8253 chip Timer Control
Clock input is jumper select-able: 2MHz (default), or 1MHz.
Clock output goes to a [[8251 USART chip]],
Clock Output may be further divided by 1, 16, or 64 in the USART chip