SerialPort: getSignals() method

Secure contextAvailable in 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:

• InvalidStateError DOMException
  • : If getSignals() is called when the port is not open. Call open() to open the port first.
• NetworkError DOMException
  • : 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

Browser compatibility