Thanks for the great comments about this product.

I agree 100% that a distress call should be put through regardless of if the unit can get a GPS fix or not. This seems a very poor decision on their part.

I also disagree with the idea of not putting through 911 messages w/o a subscription. The reality of it is IMO that this will change later anyway after they have their first mishap. Death or injury, lawsuits, and then a change of policy. Best to find a business model that works in this regard up front.

I do have a couple of specific questions. Since the unit is considered a "one-way" communications device, I am curious if the actual underlying data protocol is one way as well.

What I'm trying to get at here is when SPOT sends a message to the satellite, does it get an acknowledgment that the message was in fact received by the satellite?

What I'm worried about is if it broadcasts without confirming an acknowledgment, you could think message went out but in fact did not.

Further, is there some sort of checksum incorporated into the data protocol to ensure the message was not garbled in transmission? If so, what happens if it was? Does it re-send, give the user an error, etc?

Thanks for your report Doug!

-john