2W/4W Hybrid 1
• To connect a 2W local loop to a 4W network a circuit called a 2W/4W
hybrid is needed.
• Two wires are used between telephone subscriber terminal set and analog
line interface to minimize line cable costs.
• Transmission and reception occur in the same two wires of the local loop.
• Four wires are used for longer distance trunks between the exchange
branches in order to isolate transmitted and received signals.
• The separation of transmit and receive signals in the analog line interface at
the CO is achieved using hybrid transformer.
• EXAMPLE: MC3419 motorola IC works as hybrid transformer.
The 2W/4W hybrid performs the following operations:
• separates the transmitting and receiving signals
• matches the impedance of the 2W local loop to the network circuit
• To connect a 2W local loop to a 4W network a circuit called a 2W/4W
hybrid is needed.
• Two wires are used between telephone subscriber terminal set and analog
line interface to minimize line cable costs.
• Transmission and reception occur in the same two wires of the local loop.
• Four wires are used for longer distance trunks between the exchange
branches in order to isolate transmitted and received signals.
• The separation of transmit and receive signals in the analog line interface at
the CO is achieved using hybrid transformer.
• EXAMPLE: MC3419 motorola IC works as hybrid transformer.
The 2W/4W hybrid performs the following operations:
• separates the transmitting and receiving signals
• matches the impedance of the 2W local loop to the network circuit
