Difference between revisions of "ASYNC SETBAUDRATE (41h)"

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{{DISPLAYTITLE:ASYNC_SETBAUDRATE (41h)}}

Latest revision as of 21:19, 26 March 2020

This function sets the bit rate.

Category
IOCTL_ASYNC (01h)
Function
ASYNC_SETBAUDRATE (41h)

Parameter Packet Format

Field        Length     C Datatype
Bit Rate     WORD       USHORT

Data Packet Format

None. Packet pointer must be NULL.

Returns

If the call is made with invalid Parameter Packet values or an invalid Data Packet pointer, a general failure error is reported.

Remarks

If a general failure error is not returned, the physical device driver performs the action described in the Bit Rate field. An OPEN request packet does not cause the physical device driver to change the bit rate from its previous value. The initial value is 1200 bps.

The COM device hardware determines which bit rates can be supported on a given system. The range of bit rates supported by Function 41h is 2 bps to 19200 bps for COM ports on conventional serial devices. For COM ports on enhanced serial devices, the range is 10 bps to 57600 bps. A call with a value beyond this range fails with the ERROR_INVALID_PARAMETER return code.