ASYNC GETMODEMINPUT

Returns the modem control input signals.

Category

IOCTL_ASYNC (01h)

Function

ASYNC_GETMODEMINPUT (67h)

Parameter Packet Format

None. Packet pointer must be NULL.

Data Packet Format

┌──────────────────────────────────────────────────────┐
│Field                          Length     C Datatype  │
├──────────────────────────────────────────────────────┤
│Modem Control Input Status     BYTE       UCHAR       │
└──────────────────────────────────────────────────────┘

Modem Control Input Status

If a bit has a value of 1, the condition is on. If a bit has a value of 0, the condition is off.

Bit 0-3

:Undefined

Bit 4

:Clear To Send (CTS)

Bit 5

:Data Set Ready (DSR)

Bit 6

:Ring Indicator (RI)

Bit 7

:Data Carrier Detect (DCD)

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 current modem control input signals of the COM device.