Ubiquiti M radio

HamWAN Tampa uses the M3 and M5 radios for backhaul.

Serial port

J1 is serial port and takes a 4 pin .010 header. 115200, 8N1 is the port speed. Output is only at boot.

Top = pin1
Pin 1 = 3.3v
Pin 2 = serial data RX (from PC to Radio)
Pin 3 = Serial Data TX (from Radio to PC)
Pin 4 = Ground

U-Boot 1.1.4.2-gd9d730c7 (Feb 14 2020 - 10:52:59)

DRAM:  64 MB
Flash:  8 MB
PCIe WLAN Module found (#1).
Net:   eth0, eth1
Board: Ubiquiti Networks XM board (rev 1.0 e1c3)
Hit any key to stop autoboot:  0 
## Booting image at 9f050000 ...
   Image Name:   MIPS Ubiquiti Linux-2.6.32.71
   Created:      2020-07-15  13:58:30 UTC
   Image Type:   MIPS Linux Kernel Image (lzma compressed)
   Data Size:    1034643 Bytes = 1010.4 kB
   Load Address: 80002000
   Entry Point:  80002000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK

Starting kernel ... 

Booting...

Reset Circuit

There is a reset circuit which can be activated via the Ethernet cable. This can be disabled in the firmware, however, this still is active at boot and can put the radio into a bootloader mode. This causes the radio to come up at 192.168.1.20 and expect firmware via TFTP.

This is activated by a >15v potential on the Ethernet data lines with respect to ground. As this is totally non-standard and violates the balanced nature of the Ethernet system, it's possible to have this happen due to leakage voltage across the Ethernet.

Removing D903 completely disables this.