Which connector is used to uplink a new ISP cable modem to its wall jack?

Cable modems supplied by ISPs connect to the coaxial wall outlet using an F-type connector. CompTIA A+ specifies that F-type connectors are threaded coaxial connectors used in broadband cable internet, cable TV, and some satellite systems. They attach to RG-6 or RG-59 coaxial cable and provide a secure, shielded connection to the cable provider’s infrastructure.

The cable modem requires this coaxial uplink to receive downstream and upstream signals from the ISP before converting them into Ethernet on the LAN side.

LC (B) is for fiber optic connectors, not coaxial. RJ45 (C) is an Ethernet connector and is used on the LAN side of the modem—not on the wall uplink. Lightning (D) is an Apple connector and irrelevant to networking hardware.

Thus, the correct connector for the ISP cable modem uplink is F-type.