To which type of transceivers are fiber-optic cables connected in a router or switch?

Fiber-optic cables in a router or switch are typically connected using SFP (Small Form-Factor Pluggable) transceivers. SFPs are compact, hot-swappable modules that allow for easy installation and replacement of various types of interfaces, including those for fiber-optic communications. These transceivers convert electrical signals to optical signals and vice versa, enabling the transmission of data over fiber-optic cables.

SFPs support multiple types of fiber-optic connections and various data rates, making them versatile for different networking needs. Their design also accommodates different types of fiber, such as single-mode and multi-mode, allowing connections to various network infrastructures.

The other options do not serve the same function as SFP transceivers in conjunction with fiber-optic cables. RJ45 connectors, for example, are used primarily for twisted-pair copper cables and are not compatible with fiber-optic technology. LC connectors are used to connect fiber cables directly, but they do not serve as transceivers themselves. DB9 connectors are typically associated with serial communications and therefore do not relate to optical networking. Thus, the use of SFP transceivers is essential for the effective integration of fiber-optic cables in network devices like routers and switches.