How can i access serial console using uart for this router?

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i have dn8245v-56 i want to know where is the tx and rx pin

Did you check both sides of the PCB? If it's not marked anywhere, then you'll probably need to take the RF-shielding off, find the pinout of your SoC and then see, if there are two tracks going in the same direction from where the UART-pins on the SoC are and then trace where those tracks go.

On the other hand, if you want people here to try and see, if they can find the pads for you, you need to learn to take better pictures and you need to take pictures of both sides of the PCB -- you should probably also remove the RF-shield as well. That glare, for example, makes it impossible to see everything -- use indirect lighting to get good results. Also, your camera appears to have focused on the two electrolytic caps instead of on the components on the PCB.

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I don’t even see a connector placement on the board, but the bottom edge isn’t visible.

But what pin is TX and RX isn’t that important. The important pin is the ground because if you mess that pin up when connecting gnd, tx and rx you fry something when powering up.

Vcc is important but not necessary for function since you don’t use that one.

But gnd and Vcc you easily find with a multimeter. The gnd will have continuity with all the other gnd pins and the Vcc will have stable 3,3V when power on.

The tx and rx is either right or wrong, if wrong then shift them.

Thank for your response i have better pictures

These are the backside

And these are the frontside

Can i accessthe serial console for this router, it's not necessary uart maybe any other way

It doesn’t seem to have any 3 or 4 pin 2,54mm connector placement anywhere. Or any connector at all. So to do the serial connection simple seems unlikely.

Does the cpu even have a serial module to begin with?

Do you mean RS-232 when you say UART? That is a no-no if you don’t have a official console port. We talk 3,3V TTL serial standard on network devices.

Not all devices use a 2.54mm pin-header for UART. Some only provide unsoldered pads on the PCB.

Yes, it does.

UART is UART. RS-232, TTL etc. describe the physical characteristics of the connection, whereas UART is the peripheral.

I just can't trace anything from those pictures, sorry. As for accessing the console, if you can't access UART, then you'd need to hack the firmware itself and the easiest way of doing that would probably be to use an SPI NOR flasher to directly program the SOIC8 NOR flash there, but I don't think your skill level is up to the task.

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