Great Call is a big platform where users can use its services to connect hassle-free with their friends and relatives. With Great Call, you can use the simple and easy call option in case of any emergency. It has built-in functionality to generate alerts and provide a response in need. To access all these services, you will have to activate your account, and device at greatcall.com/activate. This activation works based on your mobile ‘Serial Number’. You will get this serial number on the backside of your mobile phone.