Get
a 3.3v FTDI cable. That is your serial uart you will connect to the router. Then, on the underside of the router's PCB, look for contact points labeled TX RX, GND
Connect the RX of the uart to the TX contact on the router.
Connect the TX on the uart to the RX contact on the router.
Connect the GND on the uart to the GND on the router.
Check device manager after plugging in the uart cable, and see which serial port it got assigned.
Open PuTTY, and choose "serial" as the connection type.
type in the serial port the cable had assigned to it (com1, etc)
use these connection settings (they are mostly standard)
115200 for rate
8 bit
1 bit parity
software flow control (we dont have DTS and CTS, so we cant do hardware flow control)
Once putty is started, turn on the router. You should see stuff happening almost instantly on router power-on, including seeing stuff from uboot.
wait for the router to finish booting, then press enter.
Do stuff on the console.