The cellphone is an invention that allows you to connect with people from wherever you are. Unlike the landline telephone connection, a cellphone can be in mobility, and you can establish a seamless connection to talk to anyone over a phone call. In fact, the text messaging services and the internet connection are an incredible value add towards cellphone’s primary services.
The entire functionality of the phone depends on a microchip called the SIM card. It allows you to connect the phone with the cellular network that you have subscribed for. Be it voice calls or texts, the cellular network helps you be in touch with your loved ones whenever you want. However, there are situations where the SIM card might not receive the signal. It might be because there is no cellphone tower of your network service provider. It can also be a situation where the SIM card is deactivated due to several reasons.
Just dial 911 from your phone, even if you don’t have a SIM card.
Imagine, when you are in an emergency and your cellphone network fails to connect because of the aforesaid reasons? You can still call 911 and establish the call connection.
How is it possible? This article will give you a good idea of how SIM card functions and also the technology behind connecting emergency calls when there is no SIM card in your phone as well.
Prime Functions of a SIM Card
SIM card is a tiny chip that is inserted in your GSM cellphone, that connects with your cellphone tower of the network service provider. As you call someone from the phone, the SIM card first sends the signal to the tower near your location and then connects with the person’s tower in his/her location. The receiving tower will connect with the cellphone or the landline whichever you call. So, this is how the call is connected and you can talk without any interruption.
Further, the text, as well as the data connection, works in a similar way. The data connection is established by sending and receiving data packets, thereby allowing you to connect with the internet too. You can access the Apps and mobile browsers as you do on your normal desktop as well.
How is it possible to Call 911 without a SIM Card?
While the above-mentioned being the prime function of a SIM card, there is a technological innovation that was available right from the beginning when the cellphone came into use.
Firstly, let us see how a SIM card connects with the emergency numbers when it is present in your cellphone but dysfunctional.
There must be situations where you would notice the cellphone displaying ‘Emergency calls only’. This happens when there is no signal on your phone or your SIM card is not functioning because of many reasons. But, even at this moment, you can connect with 911 for an emergency. As you call 911, the SIM card will search for the roaming tower of your network service provider. It establishes the connection, and you can connect with the emergency number and talk to the agent.
If there is no roaming tower, then the SIM card will search for the alternate tower which can be of any other network service provider too. You can still connect with 911 and talk.
Now, if your phone does not have a SIM card at all. Or if the SIM card is deactivated?
This is where you need to get to the basics of the SIM card’s functions. In general, a SIM card contains only the carrier info and your phone number. Even if your cellphone does not have a SIM card, the cellphone uses the antenna in your cellphone and connects with 911.