A Mobile Switching Center, or MSC for short, is like a fancy telephone operator for cell phones. When you make a call or send a text message with your cell phone, the MSC is the one that helps make sure it gets to the right place.
If you want to call or send a message to someone, the MSC first checks if you have enough network coverage in the area. Just like when you play with walkie-talkies or baby monitors, your phone needs a good signal to reach the other person's phone.
Next, the MSC finds out which cell phone tower you are closest to, and where the person you want to talk to is located. The MSC then does some magic to connect your call or message to the tower closest to the other person's phone.
Once that's done, the MSC keeps an eye on the call to make sure it doesn't get dropped or lost. If you move around or switch from Wi-Fi to mobile data, the MSC also helps make sure that your call or message stays connected without any interruption.
So, the Mobile Switching Center is like a traffic cop for cell phones, controlling and connecting your calls and messages to make sure they get where they need to go.