Serial communication with RS-232/422/485 protocols

RS-232 is a mature point-to-point protocol for serial communication. Use the RS-232 blocks to communicate with other devices by using the serial ports built into the target computer. You can also use the blocks to connect to dedicated boards that are compatible with PCI-standard bus architectures, such as PCI, PXI®, and PC/104.

You can configure the blocks to support the following boards:

  • Serial ports on the target computer mainboard

  • Third-party Quatech® PCI boards manufactured by B&B Electronics (

  • Third-party Commtech PCI boards (

The Commtech/Fastcom and Quatech boards and blocks will be removed in a future release. Do not use them in new models. Instead, use boards and blocks available from

For detailed information about these boards, see the manufacturer documentation.

See RS-232 I/O Drivers.


ASCII Encode/Decode (Composite)ASCII Encode/Decode
ASCII Decode V2ASCII Decode V2
RS232 State (Composite)RS232 State block
FIFO Read/Write (Composite)FIFO Read/Write
FIFO Read Binary (Composite)FIFO Read Binary
FIFO Read HDRS (Composite)FIFO Read HDRS block
RS-232/RS-422/RS-485 Send/Receive (Composite)RS-232/RS-422/RS-485 Send/Receive block
Modem Control (Composite)Modem Control block
Modem Status (Composite)Modem Status block
RS-232/422/485 Board Setup (Commtech) and Interrupt Check (Quatech) (Composite)RS-232/422/485 Board Setup (Commtech) and Interrupt Check (Quatech) block
RS-232/422/485 Enable TX Interrupt (Composite)RS-232/422/485 Enable TX Interrupt block
RS-232/422/485 Filter Interrupt Reason (Composite)RS-232/422/485 Filter Interrupt Reason block
RS-232/422/485 Read Hardware FIFO (Composite)RS-232/422/485 Read Hardware FIFO block
RS-232/422/485 Read Int(errupt) Status (Composite)RS-232/422/485 Read Int(errupt) Status
RS-232/422/485 Setup (Composite)RS-232/422/485 Setup block
RS-232/422/485 Write Hardware FIFO (Composite)RS-232/422/485 Write Hardware FIFO block


fc422mexcalcbitsCalculate parameter values for Fastcom 422/2-PCI board
macaddrConvert character vector-based MAC address to vector-based address


RS-232 I/O Drivers

Learn about the Simulink® Real-Time™ library for serial communication between target computers and serial devices.

RS-232/422/485 Drivers (Composite)

To represent multiple serial devices, use composite Simulink Real-Time RS-232/422/485 driver blocks.

Featured Examples

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