RS232 / User Mode

Serial port connection and communication

The user mode allows the Syrus to interact freely with any other device through its serial port, this mode allows sending and receiving information through the RS-232 port without performing any processing on this information.

General Overview

  • Instruct Syrus to use its RS-232 RX & TX cables to work in user mode.


Syrus 4 Datasheet with Pinout

Serial Wiring Pinout (found in 14-pin molex)

Syrus Wires Syrus Signal Description
Orange RS232_TX Syrus RS-232 data transmitter cable, connect to the external accesory's data receiver cable.
Blue RS232_RX Syrus RS-232 data receiver cable, connect to the external accesory's data transmitter cable.


Once you have the external device connected to the Syrus you can configure the serial port to user mode with the apx-serial tool.

# Since apex 23.20.1
$ sudo apx-serial set --mode=user
# Before
$ sudo apx-serial mode user

Sending and Receiving Messages

Please go to the following page to check the user options, apx-serial-user

Basic operation
  1. Make sure that the baud rate is the desired one with command #1, if not, change it with command #2.
Command #1:
  apx-serial-user get --baudrate
Command #2:
  apx-serial-user set --baudrate=115200
  1. Send a message to the external accessory connected to the Syrus you can use the send command.