Pro-face PL-5910 Series, Руководство пользователя

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Chapter 8 - Using MS-DOS
PL-5910 Series User Manual
8-27
Function 15h Receive 1 Byte Data Safely
Receives 1 byte data. However, the reception buffer is not refreshed. Also, re-
sponds immediately if the buffer contains no data.
Input: AH = 15h
DX = Port Number (0 to 3)
Output: AH = Line Status
AL = Reception Data
Function 16h Enable RS485 Sending/Transmission
Used with Multi-Drop connections, via the RS-485 port (No. 2).
When DTR turns ON, transmission becomes possible.
Input: AH = 16h
Output: (None)
Function 17h Disable RS485 Sending/Transmission
Used with Multi-Drop connections, via the RS-485 port (No. 2).
When DTR turns OFF, transmission is not possible.
Input: AH = 17h
Output: (None)
Function FEh Resident Check
When the EXTCOM.SYS program is resident, returns a fixed message and the
version (number).
Input: AH = FEh
Output: BL = "Y"
BH = "A"
CX = Version Number
Carry = Clear