Few days back I had a Unifi AP which was running Tanaza firmware and I wanted to put AirOs back in it, SSH access was disabled only option left was to use serial and I has not clue how to do it, with help of Tanaza guys I was able to restore it back.
While I was searching how to take serial access of Unifi I dint find a complete guide which motivated me to write this.
I used USB-RS323 to take serial access which looks like this below,
Connect this USB-SR232 to you computer USB port and go to device manager, by doing a right click on My Computer, you will be able to see all the hardware which is connected to your system, if drivers are installed automatically then you will be able to find profile of your USB-RS232. If it’s driver missing kindly install it.
Make a note of COM* , we will need it next.
Once you have your com port now lets open putty which is used to take serial access, you putty configuration to take serial access is 115200 8N1
Open Putty put relevant serial line, COM<*>, speed needs to be 15200.
Parity and Flow control needs to be none.
After you have this setup click on open if everything is connected properly, you should be able to see black screen. If putty does not open it means, your serial port is wrong or its not connected properly.
Now connection from USB-RS232 to Unifi serial ports to be is very important, it took me good amount of time to find it out as i was a newbie 🙂
This connection needs to be made before you power on Unifi. As you can see SIN -> TX , SOUT -> RX, GND -> GND. This setup is in terms of USB-RS232, To make it very simple, SIN clearly says that its ready to Receive input and on USB-RS232 TX clearly tell it will be transmitting, so connect them together and same implied for SOUT is transmitting and RX on RS232 is ready to Receive input, this is the simple logic which needs to be used if you are taking serial access of any AP.
Power : I used native POE power of unifi, its technically possible to power AP from USB-RS232 but I dint make use of that.
NOTE : After all above connection is made power on the AP and you should be able to see AP booting 🙂
Feel Free to Contacting me if you end up in any trouble.