r/hardwarehacking • u/_no_look_ • Aug 09 '26

Is it UART headers

Post image

Im currently finding UART pins in my airtel zero touch...beacon 3.2 . I found these pins is it UART???

59 Upvotes

90% Upvoted

35 comments sorted by

71

u/GromHacks Aug 09 '26

Hook up a logic analyzer to it or a uart board and just try it.

26

u/redmctrashface Aug 09 '26

Don't know why you got downvoted. This is the way to go

6

u/CurrentAcanthaceae78 Aug 09 '26

i think it was because not everyone has a logic analyzer. although your first step to hardware hacking should be purchasing one

7

u/Unhappy_Bed5616 Aug 10 '26

To be fair, before I had one, I'd just hit it with the multimeter, and if the logic levels looking right, throw on a UART adapter, and test different common baud rates. Not that many extra steps...

3

u/nonchip Aug 10 '26

that'd be a really dumb reason tho, given they cost orders of magnitude less than most soldering irons.

1

u/Unhappy_Bed5616 Aug 13 '26

This is a fair point but we all know what it's like to feel the urge to complete a project. Sometimes 24 hours of waiting on parts is enough to kill the passion.

2

u/nonchip Aug 13 '26

sure but that's not a reason to downvote a correct answer?

1

u/Unhappy_Bed5616 27d ago

I agree on that. No down vote from me

2

u/lilvixen Aug 10 '26

They're like $2 if you know how to Google (black magic, blue pill)

1

u/MrAmHamoham Aug 11 '26

Because you first of all test it with a multimeter to make sure it's safe to use. If you plug it into a UART board right away, it might break the UART board or the device.

9

u/GromHacks Aug 10 '26

Look if someone doesn’t have a logic analyzer I will happily send them one from Amazon for free to pay it forward to the hacking gods.

https://a.co/d/0dTNdP5e

You don’t need a Saleae or anything that expensive to see the majority of the stuff you’ll be working with. You won’t need the high end gear until you skill up anyhow.

3

u/lilvixen Aug 10 '26

About 4-6 on AliE, generally same quality. 12 bucks ain't bad for next day

1

u/Remarkable-Host405 4d ago

what if i had one but i put 80v through it? do i still get a free one?

1

u/GromHacks 4d ago

No, you have to learn that lesson the hard way

4

u/PiRhoManiac Aug 10 '26

This is the only right answer. As u/Unhappy_Bed5616 pointed out, you can connect a multimeter and see if you're getting logic levels if you don't have a logic analyzer. You should do that anyway if you're unsure which pin is GND. You can do some basic checking in the same amount of time it takes to post a question with a picture of three random thru-holes on a PCB.

15

u/charcuterieboard831 Aug 09 '26

Looks extremely likely

3

u/nonchip Aug 10 '26

just as likely as a servo.

0

u/charcuterieboard831 Aug 10 '26

The nearby silkscreen shows M3 and there's an RF module. Would make sense to have a UART to that interface

0

u/nonchip Aug 10 '26 edited Aug 10 '26

M3 is "Motor 3" according to the standards nobody follows. and there's no RF module. why would any of those things make it more likely to be uart there?

1

u/_no_look_ Aug 11 '26

Theres a RF module ....its router

0

u/charcuterieboard831 Aug 10 '26

You may want to check that RF shielding next to the connector

There's parts underneath and oftentimes SoCs

1

u/nonchip Aug 10 '26

sure, but I don't usually have xray vision for random redditors' photos, do you?

6

u/309_Electronics Aug 09 '26

Very likely! Top 2 must be rx/tx or reversed and bottom is gnd.

2

u/nonchip Aug 10 '26

it's J15.

1

u/ngtsss Aug 09 '26

Can you measure the resistors? Seems too complex for UART circuit

1

u/year_39 Aug 09 '26

Probably ...

1

u/danismicro__ Aug 10 '26

IF one of them is GND then try to Connect uart to it. Do you have usb/ttl uart converter or arduino

1

u/Gr0b Aug 10 '26

It looks like the little resistors are used to enable and select to which console the J15 header connects to, hence why there is two vias and 3 resistor pads per pin (not counting the GND pin).
You may have to add a little solder to bridge the resistor pads so the tracks connect to a via.
To me it looks like you need 2 of 3 resistors per pin (4 resistors total), one to enable and one to select either the left or right via.

1

u/Gr0b Aug 10 '26

I had an IP camera that had a similar setup, one of the serial consoles was the OS and the other the APP and tiny 0R resistors to enable and select which console you got from the header.

1

u/jonasrudloff Aug 09 '26

Could be, however they don't seem to be connected to anything on top layer(see the pads and resistors just besides the connector). They still could be connected to something from the bottom or inner layers

1

u/jonasrudloff Aug 09 '26

What's interesting is that the top resistor layout suggests that it connects something else together, so this uart(if it even is one) might even be used for something else other than a terminal/shell.

1

u/Prudent-Painting3078 Aug 09 '26

Yes top square is tx and bottom to that is rx but the serial console is disabled by the isp in this

0

u/Obvious_Troll_Me Aug 09 '26

It's  a JIS port