The fastest means of two-way communication is the telephone.

Telephone communication involves the use of a device that allows people to speak and listen to each other in real-time, regardless of their physical location. It has revolutionized the way we communicate and has become an essential part of our daily lives.

There are several reasons why the telephone is considered the fastest means of two-way communication:

1. Real-time communication: Unlike other forms of communication such as telegrams or letters, which require time for delivery, the telephone allows for immediate two-way communication. When you make a phone call, the recipient can answer and respond in real-time, enabling quick and efficient communication.

2. Quick connection: With the advances in technology, making a phone call is as simple as dialing a number. Once the call is connected, you can start communicating instantly. This eliminates the need for physical travel or waiting for a response through other means, making it the fastest way to exchange information.

3. Clarity of communication: The telephone provides clear and accurate transmission of voice, allowing for effective communication. Unlike written forms of communication, which may be subject to misinterpretation, the telephone ensures that both parties can understand each other clearly.

4. Wide accessibility: Telephones are widely accessible and available to a large portion of the population. With the proliferation of mobile phones, almost everyone has access to a communication device, making it convenient for people to stay connected and communicate efficiently.

In conclusion, the telephone is the fastest means of two-way communication due to its real-time nature, quick connection, clarity of communication, and wide accessibility. It has revolutionized the way we communicate and has become an integral part of our daily lives.