Husky MP2500 Manual page 156

Parity errors on receive may be ignored, display a communications error
message (see section 14.11), or be handled by your application (see Part
3).
Note that the MP2500 does not support a fixed parity of 1, unlike the IBM
PC. This is unlikely to cause problems as fixed parity is very rarely used.
PROTOCOL
Use
To select the protocol to use for communications.
Notes
The standard protocols available are: NONE and XON/XOFF.
Other protocols may also be available, if they have been installed. Selecting
one of these more complex protocols will display an extra menu screen,
which you must use to configure it. See section 13.5.2 for further details of
these protocols.
RTS
Use
To control production of the RTS (Request To Send) handshake output on
COM2, while transmitting or receiving data.
Notes
The MP2500 uses this signal either to tell a remote device that is ready to
send data, or to prevent further reception when its receive buffer is full.
134 H MP2500 System Developer's Guide
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