ComSetEscape
- Updated2023-02-21
- 2 minute(s) read
int ComSetEscape (int portNumber, int escapeCode);
Purpose
Directs a COM port to carry out an extended function such as clearing or setting the RTS signal line or setting the transceiver mode for RS-485. The serial device driver defines the extended functions.
Not all device drivers support all escape codes. ComSetEscape returns Unknown System Error (-1) when the device driver does not support a particular escape code.
Parameters
| Input | ||||
| Name | Type | Description | ||
| portNumber | int | A number that indicates the COM port on which to operate. This number maps to the COM port specified by deviceName in the call to OpenCom or OpenComConfig. The portNumber 1, for example, may not necessarily map to COM1. (Linux) The portNumber 1, for example, may not necessarily map to /dev/ttyS0. Valid Range: 1—1,000 |
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| escapeCode | int | The escape code of the extended function. Use the following values:
CLRRTS—Clears the RTS (request-to-send) signal. SETDTR—Sends the DTR signal. SETRTS—Sends the RTS signal. SETXOFF—Causes the port to act as if it has received an XOFF character. (Linux) This value is not supported. SETXON—Causes the port to act as if it has received an XON character. (Linux) This value is not supported. You can use the following values only with the National Instruments RS-485 serial driver: WIRE_4—Sets the transceiver to four-wire mode. WIRE_2_ECHO—Sets the transceiver to two-wire DTR controlled with echo mode. WIRE_2_CTRL—Sets the transceiver to two-wire DTR controlled without echo. WIRE_2_AUTO—Sets the transceiver to two-wire auto TXRDY controlled mode. |
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Return Value
| Name | Type | Description |
| returnValue | int | The result of this function call. This code is a negative value that specifies the type of error that occurred. |
Additional Information
Library: RS-232 Library
Include file: rs232.h
LabWindows/CVI compatibility: LabWindows/CVI 4.0 and later