Hi all,
When using the USB connector as an OTG port (and thus power being fed from S1 port), do I have to cut the 5v line on the USB-cable?
I want to have UART access to the M2 NMEA stream from a Rasberry Pi module.
Or do I simply connect the raspberry pi to the S1 port? It does seem to have all the right connectors for rs232?
Hi Christian,
I don’t fully understand why do you need the OTG here, but, in general, you can connect RPi directly to the S1 port for position streaming. Also, the Raspberry Pi usually provides enough power for Reach M2 to boot, and you don’t need a separate charger.
I understand your confusion, I was confused as well 
I got it sorted out. I did however disconnect th 5v pin from the USB-UART converter ( and thus power the two units from their own USB adapter), as I was worried the converter couldn’t handle the load.
Hi Christian,
Can’t say I fully understand how the setup looks like 
However, it sounds like Reach M2 will definitely be safe in this case.
Imagine the following:
Wall-adapter to USB battery pack .
From there two outputs: to M2 and to a raspberry pi.
From M2 to Antenna
From raspberry pi to usb-uart-converter, and then to M2 using the supplied cable with black single-lead plugs (without the red 5v wire connected).
What are you up to this time? 
Continuous logging of NMEA strings for backend processing. Basically collecting points, averaging them 30 seconds at a time, and then calculating differences (mean, stdev, rms) against a known point over minutes, hours, days or even weeks. Results being presented as text and graphs using Python.
Building towards a system that can flag loss of fix or if the received position is out of margin for any reason (like atmospherics, loss of correction etc).
Example using a 50 km baseline (to provoke a higher Stdev during development )
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