I see and does that message regular cell phones? Or who do you message or SOS?
When you use the SOS it contact a global SOS first responder agency. I believe this coverage is like $25 year. If you want a plan where you get evacuated to the nearest hospital, then it's like an extra $129 year.
When you activate SOS on your inReach, there is a person on the other end who will communicate with you and coordinate with the proper responders in your location. They will stay in communication with you until your situation is resolved. (Note: This benefit is available to anyone using your inReach.)
For messages, yes it text a regular mobile cell phone. You can create fixed text message responses, which do not count towards your total for the month.
For me, I created preset messages that I used directly on the inReach:
Message 1
Starting trip. Also a Yes to a question.
Edit
Message 2
Setting up camp. Also a No to a question.
Edit
Message 3
Just checking in, everything is fine. Remember that messages are not free so maximize a message up to 60 characters.
Then there are quick text responses on your smartphone that you used with your paired phone.
Alrighty
Driving now. No cell service. Using GPS connection.
On the trail now, I'll write later.
I'm checking in, everything is okay.
I'm starting from here.
I'm stopping here.
Having lunch.
I'm on my way.
I'm going to be late.
Just arrived at site.
Yes
No