I employ the Spot Satellite Messenger to communicate while I'm abroad. This communications device uses GPS to determine position and is capable of sending 4 distinct messages and continuously tracking position. To conserve battery life, I do not use the tracking function. The following is a list of the messages and what they mean:
Sending this message alerts local Emergency Personnel of a life threatening situation. They are notified of my location. It is akin to calling 911. Along with the device, I purchased $100k worth of insurance so I won't be afraid to press this button if I need to. Aside from threats to my own life, I could use this button to summon assistance for other people. To assure friends and family that I am well if I used the SOS feature to help someone else, I will follow the SOS message with the custom message described below. Look for this to know that I'm safe and helped save another life.
This message alerts friends and family that I need help. It isn't a life threatening emergency, but a call that says, “I really need to get back to civilization” or “I need help that emergency services can't provide.” I hope to never use this out of the blue.
I send this message every night when I have found shelter and settled in. This tracks both progress and well-being.
This message will be sent to cancel a call for help or let others know the call was for someone else. This is also used to inform others of my location for coordinating pick-ups. If you see this message and don't know what it's about, completely disregard it.