Roaming is a special feature or service that allows a person to use communications in another country. All mobile networks can be conditionally divided into two groups: home and guest. In the territory of the country where the SIM card was purchased, the connection is automatically made to the first type of network.
If you go abroad, however, there are usually no cell towers for your mobile operator in the territory of another country. Your phone tries to find a local tower but cannot do so. In this case, roaming comes to the rescue. When it is activated, the SIM card can connect to the towers of other mobile operators. Your local telecom operator has signed an agreement with foreign operators in advance. This is done to use the resource of their communication towers.
Naturally, all this is not free, so you have to pay for roaming. The connection scheme when using roaming looks as follows: The SIM card is initially connected to the cell tower of a foreign operator, and then the signal is converted and transmitted to the local tower.
