A combo port is a device that supports both fiber optic as well as Ethernet cable connectors. So it has RJ45 as well as SFP port connectors. However, only one can be activated at a time. So, it is a single network interface with two connection options, wherein only one can be operational at a time. This is because they have the same port number and VLANs. On the other hand, SFP or small form factor pluggable ports and their advanced versions such as SFP+ and SFP++ are used only for fiber optic connectivity. SFP ports have a variety of connectors such as LC, SC, and more. Here are some distinguishing factors between SFP port modules and combo ports.