What is an encoder, what is a decoder?

Encoder:

An encoder is a component or device that converts digital or analog signals into another format.

In our case, the encoder is used on the transmitter (TX) side of transmission lines to convert an HDMI signal into an HDBaseT signal, for example.

Example: PT-HDBT-1010

However, an encoder is also used in converters that convert analog signals into digital signals, for example.

Decoder:

A decoder is a component or device that converts encoded signals back into decoded signals.

In our case, the decoder is used on the receiver (RX) side of transmission links to convert the previously converted HDBaseT signal back into an HDMI signal.