Networking - Time Division Multiplexing

What is Time Division Multiplexing (TDM)?

Time Division Multiplexing (TDM) is a method used in communication systems where multiple signals share the same channel, but each signal gets its own time slot for transmission.

Think of it like a turn-taking system — each signal takes turns to use the channel, one after the other, very quickly.

Real-Life Analogy: School Bus Schedule

Imagine a school bus that picks up students from different houses at different times:

  • House A: 8:00 AM

  • House B: 8:05 AM

  • House C: 8:10 AM

Each student gets a specific time slot. The same bus (channel) is shared, but everyone gets their turn. That’s how TDM works!

How TDM Works (In Simple Steps)

  1. Multiple signals are waiting to be sent.

  2. Each signal is given a fixed time slot in a repeating cycle.

  3. In each cycle, every signal gets its turn to transmit its data.

  4. At the receiver’s end, the data is rearranged back into its original order based on time slots.

Types of TDM

  1. Synchronous TDM:

    • Time slots are pre-assigned whether data is present or not.

    • Wastes bandwidth if some time slots are empty.

  2. Asynchronous (Statistical) TDM:

    • Time slots are assigned only when data is ready to be sent.

    • More efficient use of bandwidth.

Applications of TDM

  • Digital telephone systems

  • Satellite communication

  • Fiber optic communication

  • Computer networks

    Difference Between FDM and TDM (with Comparison Chart) - Circuit Globe