There are several Ethernet-style and coaxial wall jacks throughout my house, but I don't know where their cables terminate or whether they're connected at all. Our Verizon FiOS service currently enters through the ONT and connects to the router, and we don't subscribe to cable TV. I'd like to determine whether the coax jacks are connected to the FiOS installation, connected to one another through a splitter, or simply unused. If they are usable, could I connect a modem, MoCA adapter, or another device to improve wired network coverage in parts of the house with weak Wi-Fi?
I'm also trying to understand the Ethernet jacks. Do they run back individually to a central location where I could install a network switch, or might some be wired together for telephone service instead? What inexpensive tool can identify which wall jacks are connected to each other? I know there are testers for RJ45 and phone connectors, but I'm wondering whether a tester can check coax as well. I'd prefer to investigate this myself rather than pay to have new cable installed if the existing wiring can be used.
4 Answers
A cable tester with interchangeable RJ45, RJ11, and coax connections should do what you need. Plug a remote unit into one wall jack, then test the other jacks to find the matching cable. Many kits also include a tone generator and probe, which can help locate where the cables terminate—even if the far ends are loose in an attic, closet, or basement. Look for a basic multi-format cable mapper rather than an expensive network certification tool.
A small coax/RJ45/RJ11 continuity tester is usually enough for this job. Models sold as structured-wiring or cable mappers include numbered remote terminators, so you can identify each cable without needing the wiring to be connected to a live router. Avoid connecting unknown wiring directly to network equipment until you've confirmed what it is; an old telephone circuit or an unterminated cable should be tested first.
First verify that the supposed Ethernet outlets really have RJ45 connectors and eight wires. Some houses use the same-looking smaller connectors for telephone wiring. Ethernet runs normally terminate at a central panel or bundle, where each run is connected to a switch. Telephone wiring, on the other hand, may have several outlets joined together or daisy-chained. A toner can help distinguish those arrangements, but you may still need to inspect closets, utility areas, the attic, or the basement for the termination point.
FiOS service is fiber-based, although the ONT can provide Ethernet and sometimes coax outputs inside the house. The coax wall plates may therefore be connected to the ONT or to an old cable-TV splitter, but they may also be unused. If the coax is continuous and properly split, MoCA adapters can carry a network connection over it, but you need to trace the cables and check for disconnected, damaged, or incompatible splitters first. The Ethernet outlets are more likely to be useful if their cables all return to one location, where you can connect them to a switch.
That makes sense. I'll inspect the connectors and look for a central bundle before buying anything more complicated.