Adding OpenWrt support for Extreme Network AP3805i

before doing anything to the resistors we need to be sure

connect to serial with only 2 pins, GND and RX (reading)

you should be able to get clean output without TX (writing)

I already did it... Just GND and RX doesn't changed anything...

removing the resistor will fix your TX but your RX should still be possible...and still a concern...

be absolutely sure that the resistor is connected to ground and one of the pins
remove it if this is true

Yeah... Actually seems that these 2 resistors are related to TX. None of them are connected to RX. Will try to remove it just in case...

It is possible that we have combination of

  • blocked TX by the resistor
  • wrong baudrate

Nothing... And now I´m not able to type anything... Before, Im receiving some garbage input when typing something... Will try to found a replacement to the resistor that vanished during removal. LoL..

you need to bridge R175 now, leave R176 alone

Just short?

well if you have a 50 Ohm resistor that is the correct size you can do that

I am guessing you do not have a replacement resistor so short is ok

on my board, R175 was already there. that is why I said "optionally"

because your R175 is missing this is required.

BTW if you are successful, start a new forum post and link here

"Adding support for ..."

Ops... My miss, actually 175(Removed now) was there. 176 is missing

ok well....everything should have been ok

you have to bridge the one that is NOT connected to ground

and then try different baudrates

1200, 2400, 4800, 19200, 38400, 57600, 115200, 230400

Already tried several combinations from 300 to 115200, stop 1 - 2 ,data 5 - 8, Parity: none, even, odd.... Nothing readable.. (Almost a true table... Took almost 1 hour).Not sure if vendor might can implement some sort of hack to prevent serial access? Have you seen something like this?


I guarantee it is 8 data bit 1 stop bit no parity

it may be possible that a pin is tied to ground somewhere else with another resistor, but unlikely...

you can try baud rates beyond 115200

other than that I am out of ideas, just make sure the pins are correct I guess...

I´m also really out of ideas... Already try another 2 devices and all have same behavior...
Vendor might can set some "non default" baud rate to make this devices unaccessible?

the way you are doing serial is reliable with other devices?

Yes. Connecting RX connector to TX (loop) get keyboard text typed correctly...

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do you have an oscilloscope :laughing: