Connecting a serial console to the QNAP TS-409

If you want to connect a serial console to the QNAP TS-409, you'll need a 3.3V TTL to RS-232 level shifter. The serial connector is marked as CN9 on the board and is a connector of type JST PHR-4. The pin layout is as follows from left to right:

GND (white)
RX (black)
VCC (green)
TX (red)

TS-409 and serial console

Note that you have to void your warranty in order to access the serial console on the TS-409U.

Once you have connected your serial console, you can use a terminal emulation program to connect to U-Boot, the boot loader used by this device. You have to connect with 115200 baud and set the parameters to 8N1 (8 data bits, no parity, 1 stop bit). U-Boot on a separate page about U-Boot.