Well… here is some information about all that. When you have no signals you can’t make calls :- P That means your cell can not find Tower to use. But if you do not have sim card…? this will be bit different. Technically you can access the cell networks without sim card. Obviously you can not make any personal calls as these will be blocked by the providers, but they very well allow few numbers to go through. 100 or 108 (108 is used in most of the states) both of which are emergency numbers and have special permissions to access any network anytime and anywhere.
How does Emergency Calls without SIM card work?
We do have a logic here, sim card do not carry necessary parts to make a call, right…. it just have carrier information and your phone number. Sim card only holds the information that phone uses to authenticate to the network, it checks if the user is authorized/registered with them and If he has the credits…only then user is allowed to make calls. But for emergency calls, the network directly redirects the call to emergency help desk without checking your identity.
Most of the countries have single emergency number to dial in. Soon, India is too going to have a common emergency response number, says recent reports. The Telecom Regulatory Authority of India (TRAI) is planning to bring a consultation paper soon to kick-start the process of having a single emergency helpline where a call centre will receive all distress calls and then accordingly alert departments or agencies concerned depending upon the type of emergency.
Emergency Numbers in India
Very common and very old Emergency Numbers in India are Local police – 100, Fire rescue service – 101 and Ambulance – 102 which works from both landline and cell phones. There is an another new number available in selected states calls ‘Emergency response service – 108’ which is common to any type emergency like medical, police and fire emergencies. This service is available only in the states Andhra Pradesh, Gujarat, Uttarakhand, Goa, Tamil Nadu, Rajasthan, Karnataka, Assam, Meghalaya, Madhya Pradesh and Uttar Pradesh.
About SOS network
At times you get to see SOS on your mobile (mostly Blackberry I guess). The SOS indicates you can only make emergency calls. This usually happens when you are out of the service range of your provider but can still connect to other towers in case of an emergency.
If you are getting this message randomly when you are suppose to have service it probably means there is a problem with your sim card or your account was restricted for some reason.