I want to upgrade an existing product from a competitor LTE CAT1 module supplier that advertises an "xbee form factor" pinout. Just swap out the competitor's module and plug in the Xbee 3.
New system firmware of course but from what I can see the hard part can all be done in the module in microPython using DRM, just have to change the control state machine using new AT commands and provide sensor data over the serial connection.
The connectors and spacings are the same, but this so-called "xbee form factor" socket uses 4V power on pin 1, shorts pins 4,11,15 to ground, applies 3.3V Vref power to pin 13, and uses pin 20 as a power-on button.
It has all the serial connections (DIN, DOUT, CTS, RTS) in the right locations and correct polarity. ON/#SLEEP is implemented, also DTR and #RESET. So in theory I can do a hardware sleep request using pin 9 and monitor sleep status with pin 13. Pretty important because the XBEE uses almost twice the power of the competitor when active. The existing system just powers off the module when not in use, but that leaves it blind to the network most of the time. No polling, pushed OTA updates, control etc. No easy mechanism for passive OTA system firmware updates either. They can update the modem OTA but not the system.
USB connections exist to pins 6,7,8 but if I leave the USB update connector disconnected there is no conflict.
I won't be able to use the Associated LED output and will have to disable it or remove pin 15 to avoid shorting the LED driver to ground.
The system already has connections for two SMA dual-band antennae. I am assuming Verizon or AT&T supplied sims will work.
Any other non-obvious issues with this plan?