RJ45 to RJII

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 Question by William Kirkland posted 13 Dec 2005
 RJ45 to RJII
We have some printers that connect to unix server via 4 wire phone cords (rj11) and an adapter. We need to move the printers into other rooms and connect via the installed cat5 (rj45). The cat5 tests fine. The printers work fine on the phone wires. But when the phone wires plug into the cat5 patch panel at either end -- no signal. Are there ready-made adapters to match up the pins of the two forms?
 Answer by Joseph Golan posted 18 Dec 2005
Dear William,

Therer may be several reasons why this is not working.

Your original connectors [rj-11] or an RJ-14 (2 pair version of an RJ-11) should mate up fine with the cat 5 patch panels provided they are terminated with either the T568A or T568B wiring scheme on an 8 pin modular jack (misunderstood as an RJ45).

If however you have an RJ-25 (3 pair version of an RJ-11) the 3rd pair on pins 1 & 6 will not line up with a "twisted pair" on the category 5 connector pins 2 & 7, respectively. The signal would be split between 2 different pairs (one conductor from each) which may have an effect on and disrupt your data.

One other possibility is length - you may want to check the maximum distance that the printers can be from the unix server.

See this url for wiring of RJ type jacks and the

Joseph Golan, RCDD

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