Acrosser AR-ES6003FL - Manual (Page 65)

6.4 Watchdog Timer
If you set a watchdog timer, you can use it to reset the system when system
hangs up due to hardware issue. After you set the watchdog timer, the
software shall re-set the timer to re-start a new cycle before it time-out. Please
refer to Chapter 5 Software Installation and Programming Guide for how to set
the watchdog timer.
6.5 RS-232 Ports
There are three RS-232 ports on the AR-B6003. The COM1/COM3/COM4 are
connected through a male D-Sub 9-pin connector for serial communication.
The COM2 is connected through a cable. Users need to plug into RS-232 or
RS-422/485 connector. For RS-422/485, please refer to SW2, SW4 and SW5
setting. The following diagram is their pin definition and signal.
65