When networks are overloaded: messages instead of calls

Each cell of a mobile network can only handle a limited number of connections at the same time. A phone call occupies a connection for the whole length of the conversation. When very many people suddenly call at once, capacity is full and further calls fail or drop.

A text message, on the other hand, needs network capacity only for a short moment. If it does not get through at once, it can be stored by the network or the phone and delivered later. That is why official preparedness guidance recommends using messages instead of calls in emergencies.

Every call you avoid also helps others. When thousands refrain from dialling again and again, there is more room for emergency calls and for people who really have to phone.

Agree a contact person outside your region whom everyone in the family reports to. During a local event, the network in your own area is often overloaded, while connections to another region may still work better. The contact collects the messages and passes them on.

Write important numbers on paper too, for example on a card in your wallet or emergency bag. If the phone is flat, lost or broken, hardly anyone knows their relatives' numbers by heart.

Decide what a short status message looks like: where you are, whether you are unhurt, when you will report again. For example: ‘At work, unhurt, will report at 8 pm.’ One such message to the family or an agreed group saves many individual calls.

Send a short message first instead of calling. Write text, not long voice or video messages, because these need much more data. If a call is really necessary, keep it short and say the most important thing first.

Do not call again and again when it does not connect. Each new attempt adds to the network load and drains your battery. Better wait a few minutes and try again, or send a message that can be delivered later.

If the mobile network does not work but Wi-Fi does, for example a public hotspot set up by authorities after a disaster, messaging apps can send messages over it. Save your battery while doing so: dim the screen, close unnecessary apps and check at agreed times.

In acute danger, do not rely on messages to relatives. Then call the local emergency number at once, 112 in the EU. The emergency line is there for real emergencies and nothing else.

Never use the emergency number for general questions, such as how long the power cut will last or which roads are closed. Every such question blocks a line that someone in danger to life needs. For information there is radio, warning apps and the authorities' websites; during major incidents dedicated public information lines are sometimes set up as well.

Information from official sources takes priority over anything forwarded in chats. Rumours spread fast in such situations and can put people in danger. Do not forward anything you did not get from a reliable source.

Messages instead of calls only help when the network is overloaded but still there. If it fails completely, for example because masts have no more power after a long outage, no message gets through either. Delivery can also be delayed, and real-time back-and-forth is not possible.

Such cases need other routes: handheld radios for short distances within the family and neighbourhood, satellite devices in remote areas and a battery radio to hear official information. A meeting point agreed in advance helps you find each other again even without any connection.

Ideally, practise the plan once when nothing is wrong: send each other a test status message, check that everyone has the numbers on paper, and settle who the out-of-area contact is.