r/techsupport Aug 13 '22

RJ45 jack in home, unsure if data or phone Open | Networking

  • Home built in 2002
  • Jack label reads T568A, CX

How do I know if this jack is phone or data?


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u/pegrowe62 Aug 13 '22

For the record... a phone jack won't handle a data cable. The cable fitting is too big. In reverse, a phone jack is too small for the data cable. They look almost identical for someone who really isn't versed. If you can plug a phone in nicely, it's a phone jack. If a data cable fits properly, it's a data jack. Not sure how many people notice, but on the back of a computer for example, it's not like you can get a cable mixed up with another in terms of plugging them in. Each thing has only one jack or inlet where it will fit. The phone cable for a fax won't work in the data jack. It's all the same premise. :) P


u/raytaylor Aug 13 '22

The RJ45 socket is designed to accept an RJ11 plug so there can be some confusion there.


u/VeryNotSera Aug 13 '22

In 568A a phone cable should work if it's routed to phone.... this isn't really an issue anymore due to VoIP but back in the early 2000s with landlines and such it was.