ASYNC_GETMODEMOUTPUT
Returns the modem control output signals.
- Category
- IOCTL_ASYNC (01h)
- Function
- ASYNC_GETMODEMOUTPUT (66h)
Parameter Packet Format
None. Packet pointer must be NULL.
Data Packet Format
| Field | Length | C Datatype |
|---|---|---|
| Modem Control Output Status | BYTE | UCHAR |
- Modem Control Output 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: Data Terminal Ready (DTR)
- Bit 1: Request To Send (RTS)
- Bits 2-7: Undefined
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 output signals of the COM device.