6-position miniature modular plugs in 8-position sockets 2

[ISDNman]

OK folks,

I know for a fact that a 6-position plug (such as the "RJ11") can plug in to 8-position miniatur emodular jacks (such as the "RJ45" and work just fine.

And this scenario is very conveninet in structure writing scenarios.

What I would like to understand is if this is a legit arrangment, or simply a bastard style.

I have seen claims that this damages the socket pins. I have also seen one 8-postition jack (on a piece of equipment) that was molded in such a way that it did in fact work with a 6-position plug. But only one!

Let the firing commence!

 

[mikeydidit]

http://www.accesscomms.com.au/RJreference.htm

http://e-service.nexans.com/eService/mci/doc/en/RJ11.pdf

page 2

The first link is kind of cool. I had no idea so many RJ’s were out there. The second one give a description of what you are talking about the differences of the RJ-11 and RJ-45. .


Mike Jones
Louisiana State University Health Sciences center

 

[ISDNman]

Thanks Mike,

I did do some googling befoe I posted here, but I did not find that second one. That was pretty much what I was looking for, an RJ45 manufacturer allowing or disallowing the practice.

 

[cwc3]

I try to stay away from using 8 pin jacks for voice
because sure enough some nit wit will plug his
computer patch cable in to a digital extension
and nock down a whole card becuase there is a dead short on pins 3+6!!

 

[cwc3]

siemon makes the 8 position PLUG you are refering to and
it is for testing purposes only comes on there 8 pos bango
and on the STM-8 network mapper

 

[oldtimerbob]

If you are using a PBX or like type of phone system, then the RJ11 six position jack with the faceplate labeled 'Voice', would be the best bet (make sure it is white(the normal color for voice jacks), with the Data jack Blue ( the normal color for Data jacks)(again making sure it is labeled Data 1,2,3 etc.

With a lot of VOIP and IP phone systems,you will have to use an 8 pin RJ45 USOC jack for your voice. Once again, if you can make it white (the normal color for voice jacks).

Some years ago little notches were put into most RJ45 jacks so the RJ 11's would fit and the pins would line up correctly.

Good luck,
Bob

 

[skip555]

years ago , when network connections where coax and 8 conductor was either merlin or rj31x we where told to never do it.

now all we use are rj45 cat5e voice or data havent seen a problem yet .

 

[Jtodd]

Many manufactures are promoting their RJ45's as being "rj11 compatible" meaning that pins 1&8 won't be damaged by using and rj11. I have no data on whether or not that it actually works. I do have a whole campus of RJ45's that a good number of have been plugged with RJ11's and have seen very little damage to the pins. I think it is more a factor of user "touch". How did they treat the jack when plugging in and out? So most of the RJ11/RJ45 damage I've seen has been in dorm rooms.

I did find that Nexans document very intersting though. Honestly, I read it more as a legal document to get out of warrenty claims. Which is fine, I don't think a vendor should have to replace a link if an RJ11 (WExW) was used on an RJ45, but to use this as a discourage ment to use an RJ11 jack on an RJ45 plug...hmm...might be a little of a streach in my mind. Do note though, that Nexans is a European company and this document references the IEC international standards, not the TIA American standards. I'm going to have to look up what those say about the issue.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[phuzzy42]

We've used RJ45's for voice and data for the last 8 years with no problems at all. The advantage in having both wired CAT5 or better with RJ45s is that you can use the "voice" jack for a data connection or vice versa. Inevitably, there aren't enough data jacks where you need them - a user has a phone, a desktop PC, and a laptop, and you have to put a network printer there too. Lots cheaper to use the "voice" jack for data than run new drops. I've never seen any physical damage from plugging RJ11s into RJ45 jacks, and I've never seen damage to phone or computer equipment if they're plugged in the wrong places. Maybe I've just been lucky, but I'm sure I would've seen something by now if it was a major risk.

Steve Harmon
Greenfield, Indiana

 

[nightrdr]

Unless use use an adapter, plugging a RJ-11 into an RJ-45 works for a single line only. Requires an adapter for multiline use (or at least it did before I stopped doing structured cabling 2 years ago).

As for damage, if you connect a NIC to a jack that is terminated as an active phone line, I strongly suspect the first time the ringer voltage spikes due to an incoming call you will see damage.

 

[wires]

Unless use use an adapter, plugging a RJ-11 into an RJ-45 works for a single line only."

No - it will work for 1 or 2 pair (lines). This should handle most applications, POTS or phone system. (Of course by definition RJ11 is only single line but I assume you are refering to a 6 position plug when you said "plugging a RJ-11".)

Personally I terminate with the type of jack that is going to be used. 6 position for phones and 8 position for network. This cuts down on end user confusion.

 

[skip555]

"Unless use use an adapter, plugging a RJ-11 into an RJ-45 works for a single line only."

we wire to 568a then you can run two lines or a key phone .

we do everything 5a cat5e and run it ro a patch panel and then it can be voice or data depending on need