No serial output on Zyxel gs1900-8hp v2

I have bought 2x USB-TTL 3v3 cables in an attempt to debrick my devices. However, I am seeing nothing on Tera Term with serial port set to 115200 8N1. I have not tested the cables prior to this since I have nothing to test with but seeing as I am able to connect to the com ports and the cables seemingly decently crimped, I do not think both cables failed.
I have connected 3v3 to the top pin, Tx to the 2nd pin, Rx to the 3rd pin and Gnd to the bottom pin.
Is there something I am doing wrong?

Never connect the + voltage.

If there's no output, swap the RX and TX pins.

What do you by + voltage? I only see 4 pins on the switches.

Noone forces you to connect them all, don't.

+= 3v3

Ah, I get what you meant now. Yes, the +5V on my USB-TTL is left unconnected.
Or did you mean I'm not supposed to connect the 3v3 as well?

3v3 or 5v?

Perhaps you meant the pins on the usb ttl :slight_smile:

Anyway, try swapping TX and RX, and don't connect 3v3/5v pin.

OMG! Swapping the Tx and Rx worked! And I did not need the 3v3 either. Thank you!

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It ain’t magic.
Tx (transmit) from the cable that is sending out data from your computer is going to the Rx (Receiver) pin on the board that receives the data.
And the Tx pin on the board that is transmitting data from the board goes to the Rx pin on the cable that receives data from the board.

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