Learn optical transceiver types: SFP, SFP+, QSFP28, and QSFP-DD. Covers single-mode vs multimode fiber, reach categories, and how to choose the right module. In the world of fiber optic communications, optical transceiver modules play a pivotal role as interfaces that convert electrical signals to optical signals and vice versa. It converts electrical signals from a switch. When the optical module on an interface is faulty, you can run the display commands to view information about the optical module.