Compatible Models: K4-i5-4200U/i7-4500U
Note: There are two motherboard models for this model. Model 1 is PE_H81U-V1.11 (1G network card model), which only requires changing the motherboard jumper to switch, and BIOS modification is not necessary. Model 2 is PE_H81U-V1.61 (2.5G network card model), which requires entering BIOS to change the COM port working mode and changing the motherboard jumper.
- Press the power button, then quickly tap the Delete key on the keyboard to access the BIOS. Navigate to Advanced > IT8786 Super IO Configuration > Serial Port 2 Configuration. Set the COM2 Mode to RS485, then press F10 to save and exit after configuration.
2. With the power off, dismantle the unit to locate the JCOM2_SET1 pin row on the motherboard. This pin row is used to switch between RS232, RS422, and RS485 modes. When switching to RS422 mode, move the jumper cap to pins 3-4; when using RS485, move the jumper cap to pins 5-6. Note: The jumper cap is initially inserted into pins 1 and 2 by default. After moving the jumper cap, the external COM2 will become inactive!
3. Based on the requirements, connect the RS422 or RS485 cable from outside the chassis to the JRS485-422 pin on the motherboard. The pin pitch is 2.54mm. For RS422, connect 4 wires; for RS485, connect 2 wires. The pin definition of JRS485-422 is as follows:
RS485 Mode Cable Connection Illustration:
RS422 Cable Connection Illustration:
Note: RS422 requires 4 wires. Whenever possible, use cables of different colors to facilitate distinguishing between the signal types of the wires.
