ASYNC EXTGETBAUDRATE

This function returns the extended query bit rate in doublewords for a bit rate higher than 19200 bps.

Category: IOCTL_ASYNC (01h)
Function: ASYNC_EXTGETBAUDRATE (63h)

Parameter Packet Format

None. Packet pointer must be NULL.

Data Packet Format

┌──────────────────────────────────────────────────────┐
│Field                          Length     C Datatype  │
├──────────────────────────────────────────────────────┤
│Current Bit Rate               DWORD      ULONG       │
├──────────────────────────────────────────────────────┤
│Fraction of Current Bit Rate   BYTE       UCHAR       │
├──────────────────────────────────────────────────────┤
│Minimum Bit Rate Supported     DWORD      ULONG       │
├──────────────────────────────────────────────────────┤
│Fraction of Minimum Bit Rate   BYTE       UCHAR       │
│Supported                                             │
├──────────────────────────────────────────────────────┤
│Maximum Bit Rate Supported     DWORD      ULONG       │
├──────────────────────────────────────────────────────┤
│Fraction of Maximum Bit Rate   BYTE       UCHAR       │
│Supported                                             │
└──────────────────────────────────────────────────────┘

Current Bit Rate: The binary integer representing the actual bit rate in bits-per-seconds set for a COM port.

Fraction of Current Bit Rate: The binary integer representing the fraction of the actual current bit rate set for a COM port.

Minimum Bit Rate Supported: The binary integer representing the minimum bit rate (in bits-per-second) port for a COM port.

Maximum Bit Rate Supported: The binary integer representing the maximum bit rate (in bits-per-second) supported for a COM port. Depending on overall system overhead and the electrical characteristics of the hardware cables and serial device adapter type, the actual value of the maximum bit rate supported might be lower than this.

Fraction of Maximum Bit Rate Supported: The binary integer representing the fraction of the maximum bit rate supported for a COM port.

Returns

If the call is made with an invalid Parameter Packet value, a general failure error is reported and valid information is not returned in the Data Packet.

Remarks

If a general failure error is not returned, the physical device driver returns the bit rate values as defined. This function is extended from the current "Function 61h - Query Bit Rate".