Sounds like the text messages were buffered until the unit managed to find a signal...

An IP connection would be another alternative, but that too has its problems.

I like the idea of GSM, though, as it won't suffer from wires outside the house being cut. Guess it all comes down to adding "GSM signal quality" to the site survey before spec'ing the equipment )

The problem with GSM is that there is no chance of comms at busy times eg new years eve etc.

We have a specific application for it where land lines are not going to be the answer.

Will perservere until we have ascertained the limitations of the unit.

One thing I will say is that this unit is the most sensibly priced I have come across (we have been looking at this for some time) and they are releasing one with a power saving mode in the next week (again, we are very limited on power on the application we are looking at).

Once the application is finalised and in the field, I will be able to say more about it.