SerialPort: getSignals() method
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Note: This feature is available in Dedicated Web Workers.
The getSignals() method of the SerialPort interface returns a Promise that resolves with an object containing the current state of the port's control signals.
Syntax
getSignals()
Parameters
None.
Return value
Returns a Promise that resolves with an object containing the following members:
clearToSend-
A boolean indicating to the other end of a serial connection that is clear to send data.
dataCarrierDetect-
A boolean that toggles the control signal needed to communicate over a serial connection.
dataSetReady-
A boolean indicating whether the device is ready to send and receive data.
ringIndicator-
A boolean indicating whether a ring signal should be sent down the serial connection.
Exceptions
The returned Promise rejects with one of the following exceptions:
InvalidStateErrorDOMException-
If
getSignals()is called when the port is not open. CallSerialPort.open()to open the port first. NetworkErrorDOMException-
If the signals on the device could not be read.
Examples
Check whether the device is ready to send and receive data
The following example reads the control signals from an open port and checks the dataSetReady property to determine whether the connected device is ready to communicate.
const signals = await port.getSignals();
console.log(`Device ready: ${signals.dataSetReady}`);
Specifications
| Specification |
|---|
| Web Serial API # dom-serialport-getsignals |