Only blue pair works on CAT5e phone cable. Trying to convert to Ethernet
Hi everyone,
I'm trying to repurpose the original CAT5e telephone wiring in my 2008 DR Horton home for Ethernet, and I've hit a confusing issue.
The house was originally wired for telephone, not Ethernet. There are only three phone jacks in the house, and the CAT5e cables terminate at an exterior utility box.
I identified the correct cable using a Fluke T5-600 by twisting the blue pair together at one end and checking continuity at the other. I then repeated the test with a 9 V battery.
Blue/white-blue pair: 9.0 V at the other end (works perfectly)
Orange pair: 0 V
Green pair: 0 V
Brown pair: not tested after the first three results
I also tested continuity with the Fluke, and only the blue pair showed continuity.
All 8 conductors are present at the room jack and at the exterior cable, and they all come from the same CAT5e jacket.
My theory is that since the house was originally wired only for telephone, there may be a hidden telephone splice, punch-down block, or distribution point (possibly in the attic) where only the blue pair was connected, leaving the other three pairs open.
While I understand the exterior cable has been exposed to weather for years, I would have expected at least some continuity or voltage on one of the other pairs if they were simply degraded rather than completely open. That makes me think there's an interruption somewhere rather than normal weather damage.
Has anyone seen this before in homes from this era? Does this sound like a telephone distribution splice, or is there something else I should be checking before I start tracing cables in the attic?
Thanks!