How to use the SC optical module s A and B terminals

The A and B terminals on an SC optical module correspond to the transmit (TX) and receive (RX) channels, and must be connected to the matching terminals on the opposite module using SC duplex fiber jumpers.

Understanding the A and B Terminals

SC optical modules are typically duplex, meaning they have two separate channels for bidirectional communication. The A terminal usually serves as the transmit (TX) port, while the B terminal serves as the receive (RX) port. This ensures that data sent from one module is received correctly by the other module, and vice versa. Reversing the connections can prevent communication or cause signal errors.

Connecting SC Modules

1. Use SC Duplex Jumpers: SC modules must be paired with SC interface jumpers to function properly. These jumpers have two fibers, one for TX and one for RX, and are keyed to maintain correct polarity .
2. Match Terminals: Connect the A terminal of the first module to the B terminal of the second module, and the B terminal of the first module to the A terminal of the second module. This cross-connection ensures proper signal flow.
3. Plug-in Latch Mechanism: SC modules use a push-pull latch for fastening. Insert the connector until you hear a click, indicating it is securely latched. No rotation is needed .
4. Check Polarity: Some SC jumpers are labeled “straight-through” or “cross-over”. Ensure the jumper type matches the module requirements to maintain correct A/B alignment.

Precautions

• Avoid bending the fiber excessively near the connector to prevent signal loss.
• Keep connectors clean; dust or debris can degrade performance.
• Do not force the connector; the latch mechanism should engage smoothly.
• Verify module type: SC modules are less common today and may include GBIC, XENPAK, or X2 types, which have specific power and size requirements . By following these steps, the SC optical module's A and B terminals can be used correctly to establish reliable bidirectional optical communication.