These are the 3 main methods used to get an alert to SOS contacts

SMS Alert phone number

SOS Contacts will receive a predefined SMS’s which contains the sender's name, their phone number a message saying they need help and their location (link to google maps) and asking them to reply with OK@<xxx> (xxx is a unique number).

SMS messages

Email Alerts

Like the SMS with a reply code, with email a link to take responsibility will be sent, to take responsibility just press the link, there will also be a link with the google map location of the sender.
 As email is free, every time it’s used the balance on the account is unaffected, however, for SMS and phone calls there is a cost and the balance on the account reflects the usage. 

email message

Phone Alert call number

SOS Contacts will receive phone call alert that says <name> says help me, to take responsibility press 1 or 2/hang-up to ignore.

Phone number allows you to add extension numbers and delay so it will go through any automated switchboard