Netgear R6260 Serial Connector pinout help

Hi there,
does anybody know the serial connector pinout on the Netgear R6260?
I tried to measure it and GND is easy, but the other pins are zero or 3,3V.

have a nice day and thanks

Could you take a picture of the connector and board?

Since you mentioned 3.3V, it's UART, and you only need three pins (GND, TX, RX). In my experience, I've never damaged a UART by connecting TX or RX to the wrong TX or RX. Just don't connect them to 3.3V or GND. And make sure the USB-UART is using 3.3V logic.

If you want to know for sure, what pin is TX, you will need an Oscilloscope, at which point, you can watch the activity and confirm that the device is trying to transmit out via UART.

Soldered pins and tested with usb-uart.
1 pin GND
2 pin ? always zero Volt
3 pin ? always 3.3 Volt
4 pin ? always zero Volt

Tried with usb-uart to connect rx/tx to pin 2 and 4 and vice versa but never got anything.
No signal led on the uart lit up.

So... At this point, it can be very board dependent on what's going on. Some boards are missing jumper resistors for the UART, some boards don't have UART enabled, and then some boards pull some nefarious tricks such as requiring switching between UART speeds. But, before that, did you get the speed right?

You can guess the common speeds (9600, 57600, 115200), and 80% of the time, you will hit one, but it's easiest to figure this out with an Oscilloscope. Maybe if you look at similar Netgear routers, you can see what they use.

Given that it's only two wires for TX and RX, it's otherwise going to be 8n1 settings, almost guaranteed. But you have to figure out the speed. As I said, review other Netgear routers of a similar generation.

Again, a picture would be very helpful here, and could be added to the wiki, if you can.

I tried different speeds, but everytime i've got nothing.
Even if you get the wrong speed you receive normaly some gibberish. But here nothing.
As for now, i reflashed with tftp method and now it is working again, can't experiment more, because new Lockdown and i need my internet connection now.
I will take some pictures if there is time.