Hi there,

I just wanted to give a report of using the Huawai E220 in production for SMS receiving. Smsd supports it very nicely, everything worked fine in the beginning.
- after 6m, one modem started to sometimes disconnect and reconnect from usb. The ttyUSBx associated changed, so the config would not match anymore and the service would stop.
- a second modem of the same type was bought (from a different shop). This one seemed to work fine.
- after another 6m the second modem started to just break down, without any connection to the ttyUSB0 possible anymore. Only a USB power reset would make it work again.
- we tried to use the first modem again, with a script that would reset the USB power from time to time. This worked for some months, but somehow was not able to register to the network for some times, so delays of minutes to hours were normal
- at some point, it did not register at all anymore

conclusion: we now have two unusable modems, one exiting after a few seconds, the other not able to register to the network. We switched over to a Nokia 6230i for now. I would not recommend this type of modem for production use.

Cheers,
Andres

This is probably not the only answer to your problem if there are really hardware defaults, but about ttyUSBx changes, see this post

Yes, thanks, we also did something similar (via a script). This was working for a while, but then the modems just did not work anymore (one not registering, the other just shutting down after 10s after connecting). I truly believe the HW of both is now broken. Probably some cheap component that is just not made for continuous operation...