WindowsLinuxUniversal Windows 10 AppJavaReports and QueriesUser code (UMC)
WindowsLinuxPHPWEBDEV - Browser code
AndroidAndroid Widget iPhone/iPadIOS WidgetApple WatchMac CatalystUniversal Windows 10 App
Stored procedures
Closes the specified serial port, parallel port or infrared port.
  • A port must be closed as soon as it is no longer used.
  • Java Infrared ports are not supported.
  • LinuxAndroidAndroid Widget Only serial ports are supported.
  • WEBDEV - Server code This function affects the server.
PortNum is int
PortNum = sOpen("COM1", 2000, 2000) // Open COM1
IF PortNum <> 0 THEN
// Configure COM1: Rate 9600, even parity,
// 8 data bits, 1 stop bit
sParameter(PortNum, 9600, 1, 8, 0)
// Rest of process...
sClose(PortNum) // Close COM1
Error("Error while opening COM1")
sClose(<Port number>)
<Port number>: Integer
Identifier of the port used:
  • Port number:
    • Number of the serial port: 1, 2, 3, ... 32 for COM1, COM2, COM3, ... COM32.
    • Number of the parallel port: -1, -2, -3 or -4 for LPT1, LPT2, LPT3 or LPT4.
    • Number of the infrared port: 1, 2, 3, ... 32 for IR1, IR2, IR3, ... IR32.
  • Port identifier returned by sOpen (if this function was called with a port name).
    LinuxAndroidAndroid Widget Only this type of parameter is available.

Closing the port after a read or write operation

If sClose is run just after sWrite ou sRead, some characters may not be written or read. Indeed, sClose can close the port before all the characters are written or read. To avoid this behavior, use Multitask.
Res = sOpen("COM2", 2000, 2000)
IF Res <> 0 THEN
sParameter(Res, 9600, 0, 8, 0)
sWrite(Res, Str)

Using an external library: RXTX

In Java, the use of functions for handling the serial and parallel ports (sOpen, sWrite, sRead, ...) requires the presence of an external library: RXTX.
This library includes a Jar archive and one or more native libraries that depend on the operating system on which the application is run. To use these functions:
  • the Jar archive (RXTXComm.jar) must:
    • be found in the same directory as the Java application generated by WINDEV,
    • be found in the execution classpath of the application,
    • be directly included in the generated application (from the wizard for Java generation).
  • the native libraries corresponding to the operating system on which the application is run must be found:
    • in the same directory as the Java application generated by WINDEV,
    • in the path of the application libraries (librarypath).
The RXTX library and its documentation can be downloaded from: (link valid at the time this documentation was published).
Caution: The management of infrared ports is not available in Java.
AndroidAndroid Widget

Features specific to Android and Android widget

In Android and Android widget mode, the serial and parallel port functions can be used:
  • Only on serial (not parallel or infrared) ports.
  • Only with devices that support the CDC/ACM protocol (Arduino ATmega32U4) and the following USB to serial converter chips:
    • FTDI FT232R, FT232H, FT2232H, FT4232H, FT230X, FT231X, FT234XD
    • Silabs CP210x
    • Qinheng CH340, CH341A
    • Prolific PL2303
Business / UI classification: Business Logic
Component: wd280com.dll
Minimum version required
  • Version 9
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