Serial Port
This section describes how to use sos.hardware.openSerialPort() API.
Some platforms support connecting hardware via serial port, either directly via UART or via USB. This can be leveraged to integrate a wide variety of hardware into your digital signage application.
Such hardware could be, for example, printers, payment terminals or sensors.
- Before using this API, ensure that the display supports serial via
sos.display.supports("SERIAL"). - Samsung Kiosk serial connection only works over serial ports, not over USB ports.
Opening a serial port with openSerialPort()
Creates a new instance of serial port. You can then use that instance to handle the communication.
| Device type | Default value | Other values for device |
|---|---|---|
| RaspberryPi / Linux | /dev/ttyUSB0 | /dev/ttyUSB0 |
| Windows | COM3 | COM3 (typically, but check your Win machine if this does not work) |
| Samsung Kiosk | PORT1 | PORT1, PORT2, PORT3 |
| Android | /dev/ttyusb0 | /dev/ttyusb0 |
| BrightSign | 0 | 0 (Serial jack /dev/ttyS0), 1 (GPIO port /dev/ttyS1), USB:A/0 (USB-to-serial /dev/ttyUSB0) |
Serial port methods
Once you create a serial port instance using openSerialPort() method listed above, you can call following methods on it.
| Method | Description | Supported since |
|---|---|---|
onData() | Call a listener callback anytime the opened serial port receiving data. | 4.4.0 |
write() | Write data to the serial port | 4.4.0 |
close() | Close serial port | 4.4.0 |
onData()
Call a listener callback anytime the opened serial port receiving data. The listener will stop if the serial port is closed.
Since data may be either text or binary, it's emitted as Uint8Array and should be processed further according to the requirements of your application.
Javascript example
In case of binary data:
// serial port instance previously created via sos.hardware.openSerialPort()
serialPort.onData((data) => {
// data is array of numbers so can be processed as binary
});
In case of text data:
// serial port instance previously created via sos.hardware.openSerialPort()
serialPort.onData((data) => {
const dataString = [...data].map((char) => String.fromCharCode(char)).join('');
});
write()
Write data to the serial port. The data can be a string of hexadecimal digits, array of numbers or Uint8Array.
Javascript example
// serial port instance previously created via sos.hardware.openSerialPort()
await serialPort.write('68656c6c6f'); // hexadecimal string
await serialPort.write([10, 20, 30, 40]); // array of numbers
await serialPort.write(Uint8Array.from([10, 20, 30, 40])); // Uint8Array
close()
Close the serial port and prevent further communication
Javascript example
// serial port instance previously created via sos.hardware.openSerialPort()
await serialPort.close();
Errors
The following errors may occur when working with serial ports. However, they do not reflect the actual physical connectivity of the ports because Samsung b2bapi does not log these events.
| Code | Type | Message |
|---|---|---|
| 50602 | InternalHardwareError | Failed to open serial port |
| 50603 | InternalHardwareError | Closing serial port that isn't open |
| 50603 | InternalHardwareError | Failed to close serial port |
| 50604 | InternalHardwareError | Writing to a serial port that isn't open |
| 50604 | InternalHardwareError | Failed to write to serial port |