Talk:Registered jack

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Try for a table that shows the difference between RJs 10, 11, 12, 14, 45, 48.

Wall Plates and Surface Mount Boxes[edit]

I think there should be a section explaining how jacks are inserting into various types of telecommunication equipment like Keystone wall plates and surface mount boxes. In a professional job, you would not terminate a cable to a jack without securing it to something. Chewbaggins (talk) 26 May 2009 —Preceding undated comment added 21:16, 26 May 2009 (UTC).

Jacks do not need to be "secured". Common examples include telephone extension cables with 4P connectors, a plug at one end and a jack at the other, where the connectors and cable itself are not secured to anything. Also jacks are found in so-called couplers (a telephone cable gender bender), for joining two telephone cables by their plugs. The coupler is not usually attached to anything and so 2 jacks are in fact not "secured". It is an important distinction that an extension cable uses a connector of each sex to extend a cable. Regular telephone cables for instance are terminated with two male plugs at each end to connect a telephone to the phone system.

It should perhaps be emphasized that telephone line cables are usually cross-wired and that Ethernet network line cables use straight-through wiring. This is significant if using 8P8C couplers to extend a network cable (which is not really recommended) since they exist in two "flavours", cross-wired for telephone use and straight-through for Ethernet use. Cross-wired as used above is not ambiguous in that each individual wire is considered. So called cross-wired Ethernet cables are not fully cross-wired cables but rather cross-paired and then only pairs 2 and 3 are switched while pairs 1 and 4 (if present),and their wires, are still straight-through, which is why the adjective "Ethernet" is included to emphasize the specificity of such a cable's wiring pattern. (talk) 17:25, 19 November 2010 (UTC)

Naming Confusion[edit]

The naming confusion section refers to RJ11 as "six-position" and then in the next sentence "The four-position RJ-11". The picture labels the four pin plug as "RJ11".

What the picture labels "RJ11" is in fact a six position plug. And it has 4 pins. The two outermost slots in the plug don't have pins in them. Hence, this is a "6P4C modular plug." -- Bryan Henderson 23:32, 30 July 2006 (UTC)

It also suggests that RJ11 is a two wire standard. The source above disagrees with this. I don't like to do it, because I don't know enough about the subject - but I'd suggest removing this "naming confusion" section until it actually addresses the naming confusion clearly.

DB: RJ11 uses a 6 position mini- modular jack, but only pins 3 and 4 are used. Other 6 position RJs use 4 pins. Knowing it's foolish to have to stock 6P2C and 6P4C jacks, CFR 47 Part 68.500 states "Note: This jack is depicted equipped with 4 contacts; it may be fabricated with it's full 6 contact capacity." Similar notations were made for "some" other jacks.

RJ11 is definitely two wires. I don't know what source above disagrees, but that needs to be fixed. -- Bryan Henderson 23:32, 30 July 2006 (UTC) has discussion on this subject by some people who are keen on getting it right. The feeling I get is that RJ-xx is not the correct name for the plug or socket, but is in fact the wiring standard. From that discussion:

Just for the record, there are generally only two types of modular plugs and jacks. The six position, commonly referred to as RJ11, and the eight position, commonly referred to as RJ45.
The six position can be wired with two wires on pins 3/4, therefore an RJ11. This same plug can be wired with four wires on pins 3/4 and 2/5, thus becoming an RJ12, 13 or 14. Finally, this same plug can be wired with three pairs on pins 3/4, 2/5 and 1/6 to become an RJ25 wiring configruation. So, as you can see, it's not the actual plug that determines the "RJ" number, it's how that same plug is wired for the different configurations.

--AndyP 17:03, 2 December 2005 (UTC)

You're right, it's a confused mess, For example RJ12 here says it refers to a 6 with 4 connections used but the article i get to when i click on RJ12 Says otherwise. Also while you could use a 6/6 connector and only use 2 or 4 pins the vast majority of cables i've seen don't and it would be more of a pain to wire only two wires to a 6P6C than to a properly designed 6P4C. -- Plugwash
Yeah, I think the only way to save this article is to start over. I'll see if I can do that, but it will be hard since I don't have the 1970s documents that would have the final word on what these terms mean. I think we need to split this into two articles: registered jack, and modular connector. And the corruption in the RJ45 name is so severe, that I think we have to treat it as the legitimate name of two independent things and let the RJ45 article cover the common, technically incorrect, usage (i.e. RJ45 = 8P8C modular). We also need to remove the TIA-568 standard from the RJ45 article. -- Bryan Henderson 23:32, 30 July 2006 (UTC)
OK, I did it. New modular connector article describes physical connectors and registered jack describes registered jacks and refers to modular connector article. RJ45 article describes the other "RJ45".
But now I see various other articles on specific registered jack types with the same redundant and incorrect information. I will now try to make those consistent. I suspect some of them would work better as a few extra words in registered jack instead of a separate article.
(Unfortunately, I forgot to log in; the anonymous updates today are mine).

Bryan Henderson 21:47, 18 August 2006 (UTC)

Am I the only one who is thoroughly confused by the whole "USOC" section ? It seems to contradict itself every other sentence.

--adaptr (talk) 12:46, 19 December 2007 (UTC)

Where is 47CFR68.502?[edit]

DB: FCC CFR47 Part 68.502. CFR is Code of Federal Regulations

I checked the GPO Access site, and there is no 47CFR68.502; at least, not in the latest revisions. Why is this citation still here? Nulbyte 01:55, 5 May 2006 (UTC)

The authority was transferred to a private organization in 2001 and section 502 repealed.. I added that information in June, but forgot to remove the reference to 47CFG68.502. I've done that now. -- Bryan Henderson 21:34, 30 July 2006 (UTC)
Given that the current private standards seem to have nasty redistribution conditions attatched we imo should if possible link to the original pre-delegation standards as well (US fedral standards are PD aren't they?) Plugwash 17:28, 27 September 2006 (UTC)

RJ12 often used for 6P6C[edit]

DB: Now that IS a problem. You absolutely cannot use a RJ12 for a 6P6C. RJ12 is not hardware, it is a wiring plan, and the 6P6C miniature modular jack, obviously, IS hardware. You must use the 6 "position" mini-modular jack for RJ14C/W. It's plan uses only pins 2 through 5, so you can use either a 6P4C or a 6P6C... that part is a "who cares?"

Is this another example of the kind of misuse we have seen with RJ45? Lego (with reference to the mindstorms nxt) and microchip (with reference to the icd2) both seem to use it. What other uses does a 6P6C connector have and do its users also reffer to it as a RJ12? (i'm not discussing right or wrong here, just actual use) Plugwash 00:25, 11 September 2006 (UTC)

DB: Other uses of 6P6C: RJ18C/W, RJ25C, RJ1DC,

DB: You should think in terms of right and wrong. It will make more sense if you do.

Simplify! Just use RJ45 jacks wired T568A and you can use it for phone - 1,2, 3 and 4 lines; the majority of phone systems; LAN; various media distribution (HDTV) systems; and more - that's basically become the d-facto standard (kinda). For example, just plug an RJ11,12, etc into a RJ45 jack, plug the other end of the wire into a phone distribution module in the distributed wiring enclosure and BAM it's a phone jack. Or plug your RJ45 from your computer into the jack with the other end of the wire into a network router in the distributed wiring enclosure and BAM it's a network port. - So again, just use RJ45 jacks wired T568A. (in MOST situations-there are always exceptions to everything...) —Preceding unsigned comment added by Sbg1959 (talkcontribs) 13:37, 10 November 2007 (UTC)

DB: That simplifies nothing. RJ45 is NOT a jack, it's a wiring plan. Standard wiring configurations T568A and B use the 8 position min-modular jack and provide Standard coding (color code, etc) for four cable pairs. T568A and B are specific to wiring "within" a customer premises. Trying to use RJ45 as you discuss, is irrelevant.

Grounding[edit] discusses shielding and screening in a cable and mentions that it is ineffective unless a shield or screen is grounded. This is probably achieved through the jack, but how? All the jacks in this article are plastic with no mention of a ground.
Regards, ... PeterEasthope (talk) 05:04, 2 February 2008 (UTC)

There is a variant of the 8P8C "RJ45" connector with contacts on the sides for the screen used for shielded twisted pair ethernet wiring (most cards/hubs/switches have the contacts for a shield but shielded wiring is rarely used in practice). I don't know if and where this is standardised and whether similar things exist for other sizes. Plugwash (talk) 15:21, 2 February 2008 (UTC)

Thanks Plugwash. Does anyone have a picture of one of these? Anyone care to mention under "Uncommon types"? Perhaps grounding warrants a new heading.
Regards, ... PeterEasthope (talk) 15:36, 13 February 2008 (UTC)

You can find pictures of shielded and unshielded plugs for cat5e and cat6 (both for stranded and solid cables, but I have no idea of the differences between them) in [1] (I hope this is not considered spam) Fernando Gutierrez (talk) 20:37, 21 July 2009 (UTC)

"The middle two can be plugged into the same standard six-pin jack, pictured"[edit]

There is no "Middle two", methinks. What's a better way to say this? (talk) 15:35, 13 November 2008 (UTC)

Registered or Registration[edit]

The article is headed "Registered jack" (which makes sense according to it's definition) but contains frequent references to "Registration jack", which makes no sense to me. Is this just sloppiness/typos or is there some rationale to it? —Preceding unsigned comment added by (talk) 13:48, 7 April 2009 (UTC)

Seems to be bad editing. It first appeared in revision 245804589 I've corrected these. Tothwolf (talk) 01:21, 8 April 2009 (UTC)

DB: 8/10/09 I hope this will help: Jacks are NOT registered, telephones ARE registered. The FCC Registration Program outlines the technical requirements, at The Network Interface, for telephones to be connected to the "Network," and it details the NI type and their wiring for use by both the Telco (jack), on their side of the NI, and the Customer (plug) on their side of the NI (aka the Customer Premises). The NI connector identifications are actually Universal Service Order Codes (USOC) which are used by the Telcos, and the codes were adopted by the FCC and the ANSI Standards bodies. They are correctly called Registration Jacks because they are "of " the registration program, but are not registered.

DB: Also, the codes such as RJ11 define a wiring plan at the NI, not a jack type (6 pin mini-modular). A particular jack type may serve many different wiring plans, i.e., the 6 position mini-modular jack is used for the following.... RJ11C/W, RJ14C/W, RJ18C/W, etc.

DB: And finally, jacks used within the customer premises, but NOT at the NI, are NOT Registration Jacks, and are correctly called by either their type (for example 8 position mini-modular) or by a non-NI code, for example, "T568A" or "T568B," etc, which use the 8P8C jack.

What about 6p8c jacks?[edit]

DB: You can't put 8 connections on a 6-pin jack. No such thing exists.

Our university dorms used 6p8c jack and plugs to deliver networking in each customers room until very recently. I didn't see any mention of jacks that have a higher 'c' than 'p' numbers. Should they be in the uncommon section? Larek (talk) 13:01, 30 April 2009 (UTC)

You cannot fit 8 conductors into a modular plug with 6 positions, that's physically impossible. (talk) 11:17, 25 July 2011 (UTC)

Where's the actual info?[edit]

"True RJ45" redirects to this article, but this article does nothing to define "true RJ45". Much of this article is a listing of what registered jacks are not. "True RJ45" is mentioned but never defined and all RJ45 links in this article point back to the 8P8C page which says "the true RJ45 uses a different 8P modular connector type". If RJ45 doesn't use 8P8C, then RJ45 shouldn't be used to link to the 8P8C page. Can anyone provide any information regarding the actual RJ45 specs? What's the physical jack type? What's the wiring pattern? —Preceding unsigned comment added by (talk) 15:03, 13 July 2009 (UTC)

It is currently quite a mess, see Talk:Modular connector#Merger proposal. --Tothwolf (talk) 15:23, 13 July 2009 (UTC)

DB: RJ45 ABSOLUTELY uses a 8 position keyed miniature modular jack; programmed. It "can" be 8P4C, because only a single cable pair is used (pins 4 and 5), plus a programming resistor is placed on pins 7 and 8. It's use really should be obsolete by now, and trying to use "RJ45" nomenclature inside the customer premises will only continue the mass confusion.

I was there hooking up modems to RJ45 and RJ41 NIs these jacks both used a 8p8c Keyed modular form factor Pair 1 the center pair pins 4 and 5 connected to the Tip and Ring pins 7 and 8 connected to a Fixed Loss Loop/Dry loop for rj41 and a resistor for rj45 (the resistor was located in the JACK not the Plug) some of the Jacks had a switch to select either fll/pr so they could be used for either - this resistor/dry loop was used to tell the modem what the signal loss was from the CO to the premises.

Notes on RJ21[edit]

These pages seem to be an attempt to correct the "RJ" vs incorrectly applied usages of the RJ terms; Therefore

note the passage that says "RJ21 connectors are used to connect Ethernet ports in bulk from a switch with RJ21 ports to a CAT-5 rated patch panel, or between two patch panels. A cable with an RJ21 connector on one end can support 12 8P8C "RJ45" connectors or Ethernet ports on a patch panel."

In this case shouldn't it refer to the connector (genearally called an "Amphenol" connector) not RJ21 Amphenol 25-pair/50-position "Micro Ribbon" or CHAMP see or ( (the 36 position often called the centronics Parallel connector - which also actual refers to how its wired and not the connecor's actual name) —Preceding unsigned comment added by (talk) 21:15, 8 December 2010 (UTC)

USOC - u?[edit]

"Uniform" or "Universal" Service Order Code - the snippet view of US CFR shows "Universal", but "Uniform" is popular among many cable books. Or did it change? --Wtshymanski (talk) 16:54, 31 August 2011 (UTC)

RJ45S Picture[edit]

Can I Request a picture of the RJ45S Keyed Jack be added to the article? Never seen one, and keep on getting pointed to 8P8C "RJ45" Connectors. Would a comparison picture help illustrate the difference, or do they look the same on physical inspection? (talk) 15:35, 13 February 2012 (UTC)

Name for offset-tab connector?[edit]

I am trying to locate a source for offset tab registered jacks, as a sort of keying to keep people from plugging things into the wrong connector (I hate USB-over-CAT5). However I have no idea what the official name is for this to try to search for product options.

I know older terminal devices like DEC VT-420's used them for keyboards. Someone must still be making 8-pin versions of the plugs and sockets, with both a left-offset and right-offset tab.

DMahalko (talk) 19:48, 9 November 2012 (UTC)

It looks like the current robotic LEGO Mindstorms uses offset-tab registered jacks:
Prise LEGO NXT femelle.jpgLego mindstorms nxt cable.jpg
I still can't find any references to the official name for this connector style. -- DMahalko (talk) 19:03, 7 December 2012 (UTC)

Polarity on RJ11 & RJ14 should always be reversed (like patch cables)[edit]

Particularly in DSL cables, but also generally, polarity is reversed on POTS / PSTN cables.

E.g., center wires will be Green / Red on one end and Red / Green on the other on an RJ11.

Wiring on an RJ14 will be

Yellow / Green / Red / Black

one end, and on the other, exactly reversed,

Black / Red / Green / Yellow.

RJ14 port[edit]

Just discovered that the Wii controller for Guitar Hero had an RJ14 port, intended to support peripherals, but nothing was ever released.[] It would be nice if this info could be somehow included in the article. --Auric talk 19:37, 20 September 2013 (UTC)

No. This has nothing to do with an RJ interface. This would be a use of a modular connector for something completely unrelated to registered jacks. Kbrose (talk) 16:25, 11 December 2014 (UTC)

Italian link[edit]

Link to Italian page is missing. I've tried to add it, but I get an error. At the same time I see that the corresponding Italian pages in all other languages, i.e., are missing the link to this English page. How to solve it? I don't know how. --Oriettaxx (talk) 07:55, 8 January 2015 (UTC)

Picture of RJ21 connector[edit]

I believe the image of the RJ25 connector is incorrect. The arrow pointing to Pin1 is (i think) actually pointing to pin 6. — Preceding unsigned comment added by Conjac (talkcontribs) 08:58, 6 November 2015 (UTC)

The bottom plug is correctly labeled. What is less clear is what the intention was for the connector in the top half. The other end of the cord? Depending on that intent it could be wrong or right. I might be tempted to cut the top half off. Kbrose (talk) 15:18, 6 November 2015 (UTC)
Likely intended to show the 'plug' as the 'in the know' insiders { SORRY, it is / was the way we were taught to ' view it ' } view of it { bottom half } and for the non-tech' savvy 'flipped right side up' as many would not set it on the "release" to get a picture of it { as they would likely set it as it appears to be oriented in top half of the picture }.
As i have in the PAST used Wikipedia in a manner it founders and supporters likely never intended it for { reteach @ / ~ research for a tech project ( s ), i KNOW a LITTLE about , BUT ENOUGHT about to put myself ' in danger ' or the EQUIPTMENT IN JEPORDY @ / ~ THE PUBLIC IN HARMS WAY... IT IS IMPORTANT to all that i familiarize myself with the designers thoughts and intended use of the Equipment @ / ~ designs @ / ~ NI @ / ~ ETC... "WHILE it is wildly unlikely that a crossed wire ' in todays tech' advantaged world ' would cause little more than a BLOWN FUSE @ / ~ A MINOR inconveniences to me, i like to tech it out first ©®™℠ J So9-10 ©®™℠"
The content, at the above section ( s ), about "Polarity on RJ11 & RJ14 should always be reversed (like patch cables)" @ / ~ "Modular Jack Wiring needs Clarification" @ / ~ "Naming Confusion" and some equally strong objections at other articles is why these discussions should be at least referenced in the article ( s ), @ / ~ or added to the 'see also' section imho { BUT STRONGLY WORDED opinion } (talk) 13:11, 13 November 2015 (UTC)

For the love of God[edit]

Could someone add the info at in terms of what all the RJ-45 wires' uses are?

It's been so long, and, this article doesn't even state what all the 8 wires do, in terms of receive data, transmit data, and bidirectional.

Thanks. — Preceding unsigned comment added by (talk) 18:46, 14 November 2016 (UTC)

Contradiction About Physical Size[edit]

This page says the RJ standards DO define the physical dimensions: This page says the RJ standards don’t define the physical dimensions: I have no horse in this race, but as a casual user who just stopped by, I saw the contradiction and figured I'd mention it to someone who knows better. (talk) 15:15, 11 May 2017 (UTC)Joe40.135.213.18 (talk) 15:15, 11 May 2017 (UTC)