The document discusses different types of communication classified based on direction of communication and transmission mode. There are three types of communication based on direction: simplex where communication is unidirectional, half-duplex where each device can transmit or receive but not at the same time, and full-duplex where both devices can transmit and receive simultaneously. Communication is also classified based on transmission technique: baseband where the original signal is transmitted directly and broadband where the signal is modulated before transmission.