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TOPIC: How To Connect RJ45 Plugs Into RJ11 Jacks

How To Connect RJ45 Plugs Into RJ11 Jacks 11 years 5 months ago #19640

This mod simplifies the application of a "noise resistant" twisted pair between RJ11 DSL modem and phone jacks, something that needs to be done on occasion but seems to be a bit of a chore with current techniques. It's done by enabling a network cable's RJ45 plugs' pins 4-5 to "connect directly" to the RJ11 phone jacks' 2 center conductors,

We posted this mod in the "RJ11 to RJ45" thread but that subject title does not suggest it as well as this title, so this new post to share with hopefully more people.

After learning "at this forum" that RJ11 plugs "fit" into wider RJ45 jacks, we measured and compared RJ11 6P4C plugs and RJ45 8P8C plugs, (P = "positions", C = "conductors"). Found that the ONLY difference was in their width, .375 inches vs .450 inches, all other parameters were exactly the same, including the latches and pitch between conductors/grooves. Quickly inserted a "flat cutter/router" into our little "Dremel" rotary tool, and "narrowed both plastic plugs" of a 25 ft RJ45 network cable "evenly" until they fit into RJ11 jacks. Replaced a 25 ft phone cable between our RJ11 DSL modem and phone jacks with this modded RJ45 network cable and "bingo" works. No need to hunt for adapters, or mess with performance degrading RJ45 female/keystone jacks with short RJ11 phone cables at each end. And done carefully, the outer conductors are not exposed...even if they were, they are not used.

The mod also connects network pair #2 (pins 3-6) to the outer conductors of 4 conductor phone cable, but that pair is normally not used. Hope this helps whenever needed.

Re: How To Connect RJ45 Plugs Into RJ11 Jacks 11 years 2 months ago #21204

"Bump"...esp since we referred to this thread in another reply.
Makes it easier to find on page 1.
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