SFP-GE-LX-SM1550: This identifies the module as a Gigabit Ethernet Small Form-factor Pluggable (SFP) transceiver. "GE" indicates Gigabit Ethernet, "LX" means it is designed for long-wavelength transmissions over long distances, and "SM1550" specifies it uses single-mode fiber at a 1550nm wavelength.
1.25G 3.3V 1550nm DDM 20KM SC: This outlines the module's specifications:
1.25G: Supports data rates up to 1.25 Gigabits per second.
3.3V: Operates at a voltage of 3.3 volts.
1550nm: Uses a 1550 nanometer wavelength.
DDM: Includes Digital Diagnostic Monitoring, allowing real-time monitoring of the module's performance.
20KM: Designed for transmission distances up to 20 kilometers.
SC: Utilizes an SC connector type.