Differential signalling

Differential signaling is a way for two devices to talk to each other using special wires, like a telephone line. Let's imagine you have two friends who want to send secret messages to each other using cups and a string. If one friend talks into their cup, the vibrations will travel down the string and be heard by the other friend. This way, they can have a private conversation.

Now, in differential signaling, instead of cups and a string, we use special wires called a "differential pair." These wires always come in pairs. One wire is like a positive wire, and the other is like a negative wire. The positive wire receives a signal, while the negative wire receives the same signal but in the opposite direction.

Imagine you want to send a secret message to your friend using a flashlight. However, you are in a very bright room, so the flashlight is not very visible. To make it easier for your friend to see the flashlight's signal, you could turn off all the lights in the room except for one bright lamp. Now, your friend can easily see the flashlight because it stands out against the bright light.

This is similar to how differential signaling works. The two wires in the differential pair carry opposite signals, like the flashlight and the bright lamp. When one wire receives a signal, the other wire receives the opposite signal. This makes it easier for the receiving device to pick up and understand the signal, even if there is some noise or interference.

In the example of the cups and string, if your friend accidentally knocks the cup or if there is a loud noise, it can be hard to hear the message clearly. However, if you and your friend use a phone instead, with one cup for your voice and another cup for your friend's voice, it is much easier to hear and understand each other.

Similarly, with differential signaling, if there is some interference or noise that tries to mess up the signal while it travels through the wires, the receiving device can compare the two signals that come through the two wires. It can then understand the actual signal by looking at the difference between those two signals. This helps to reduce the effects of any noise or interference and make sure the message is received correctly.

So, differential signaling is like a special way of sending messages between two devices using special wire pairs. It helps them communicate more clearly by sending opposite signals and using the difference between those signals to understand the message, even if there is some noise or interference.