Sending SMS with GSM7 characters

[Amm0]

I can externalize most of the complexity into library code (I’ve found and extended https://github.com/xlab/at in the past month), and I need a proxy in front of it anyway for authorization, message queueing and delivery notification callbacks. From there, the cost in terms of complexity/effort to talk to a serial interface vs. the RouterOS API is approximately the same.

Something like this opens up the AT port (you need to tweak channel, port, tcp-port, etc), but this is the “just” the easy part:

/port remote-access add port=usb1 protocol=raw channel=1 tcp-port=9999

I didn’t know this was even possible.

Quite the rabbit hole. But why I mentioned that “remote-access” – basically could run the Go code on the RPi, but have the xlab/at library use a TCP port that exposes that Mikrotik’s AT channel using the command above. Don’t know Go or that library, but should be able to convert TCP socket to an the os.File used by xlab/at. When Mikrotik supports containers, you code could theoretically run as a Docker on the Mikrotik (still likely have to use the remote-access TCP port even then, see http://forum.mikrotik.com/t/v7-1rc3-adds-container-support/151712/251)

On the Mikrotik side, you’d need to make sure there was an AT channel to even expose via /port remote-access. So there is also

/system/serial-terminal port=usb1 channel=1

you can use to test that AT commands even work. Again play with port/channel &

 /port print

will show the number of channels for the modem in the SXT. Some are AT, other may be NMEA (GPS) or “Qualcomm Debug” - all depending on RouterOS version/modem type/mode. And the port names sometimes are usb2 etc…

And, if you were only using the SXT for SMS/AT stuff, then you might be able to use

/interface/lte/settings/set mode=serial

which likely get you more ports (but you’d lose the LTE interface on the Mikrotik). I for sure can’t see it work, but might be able to essentially “proxy” the LTE modem module via serial-to-TCP. How fast, I dunno.