Ready For Europe

The 4 volt power supply for the cell modem arrived last week, so on Friday night I soldered it up to the cell modem and connected it to the 5 volts from the new 7-port USB hub which had also recently arrived. The documentation for the 4 volt supply claimed that there were two 4 volt output pins on the little circuit board, so I picked one of them, but after an hour or so of frustration realized that only one of the output pins seemed to be functional. Not sure if that was a fault of the documentation or the board itself, but based on the remainder of the documentation I suspect the former. The documentation for the power supply and cell modem are scattered throughout a number of places on this site: https://itbrainpower.net/. Personally, I much prefer having a single product PDF, rather than having to flip through multiple pages on the web. It just seems so much easier to find what you need later on, if you can open that one document every time.

So once the correct 4 volt output was connected to the cell modem, some LEDs flickered on, and when the power button on the cell modem was pressed, a green light flashed on and off ~ every 1.5 seconds. Something in the documentation indicated that this was as it should be. I then downloaded and installed the Windows drivers, thinking that it might be easier to test out in Windows and confirm that it was working. Indeed a number of new serial COM ports showed up in Device Manager, but the test program the documentation referred to for Windows was not available, and did not seem to be readily available on the Internet. Oh well, back to the Pi for testing then. After a few hours of careful reading and searching, I was able to find out how to correctly (I think) set the Compute Module for use with the modem.  This involved specifying the Bell APN information, and downloading some Python serial libraries to work with the modem sample code. Running the sample code appeared promising at first, as it found the chip device number and SIM card ID, but it was unable to establish any sort of a wireless signal, and did not actually appear to make any sort of wireless connection to the Bell network.

Looking through my purchase records, it turns out that I actually bought a cell modem intended for Europe. So I'm guessing that it works at 900 MHz / 1800 MHz, instead of the frequencies used in North America (850 MHz / 1900 MHz). There is a North American model available, so I ordered it and should have it in a couple of weeks. Hopefully that is the only other obstacle remaining before getting a working cell connection. Maybe the European modem will be useful someday if I ever sell anything overseas!

In the meantime, I can use WiFi for network connectivity software and testing purposes. I'm still working on some client / server software for communications between AMOS and a PC (or phone) and hope to have a simple version of it ready before the massive block of snow and ice in our pool melts. I noticed that there are large sections of the St. John River that are free from ice, but I'm too nervous to do any emergency kayaking at this time of year :-).