Talk:BNC connector

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I am starting to doubt the origin story of the BNC[edit]

I am starting to doubt the common wisdom that Neill (Bell Labs) and Concelman (Amphenol) developed the BNC and named it after themselves.

Instead, it would seem that Salati invented it and named it after the N-type and the C-type (and not directly after Neill's and Concelman's names).

I suspect that someone saw the name "BNC" and made a mental leap and incorrectly assumed that Neill and Concelman must have developed it. And now we're all parroting the same.

Here is my evidence:

Do you have any insights into this? (Does it even matter?) — Preceding unsigned comment added by DavideAndrea (talk • contribs) 19:35, 2 March 2021 (UTC)[reply]

@DavideAndrea I'm not sure this makes any of it less murky, but I've just come across Octavio M. Salati#Role in BNC connector development while googling the patent (your link took me to a 404 page).
I don't think the suggestion in this article is that they named it, just that it was named after them at some point. But it seems we don't know what point that was, or who did the naming.
My feeling is that someone naming it after the N and C connectors would very likely intend an implied reference to Neill and Concelman as well, but of course I'm just guessing.
I must say I've wondered how two engineers at different companies would end up getting together to design a new connector. It does seem much more like something one person would do. Musiconeologist (talk) 01:28, 18 March 2024 (UTC)[reply]

SMA connector[edit]

What about the SMA connector, doesn't it deserve a page? For the TNC it is stated impednace and typical bandwidth range. isn't that practical also for the BNC? 50 and 75 ohms or does it exist even more varieties? In the link it says use up to 2.4GHz but I have seen specifications up to 4 GHz (http://www.amphenolrf.com/products/bnc.asp) —Preceding unsigned comment added by 130.225.79.64 (talk • contribs) 13:03, 22 August 2005

Merging pages[edit]

I would like to suggest merging the pages

into just a single page, similar to the German page. The new page could be called radio-frequency connectors. There are a lot of commonalities between the many standardized plugs, and the minor differences and their historic relatinship are much easier to explain if they are all on a common page. I also believe, it is easier for reader to get an good overview if the material is not spread across numerous tiny stub articles, as it the case now. A single page would also help people who want to identify a connector. Most of these connectors are even defined in the same IEC and MIL standards. Opinions? Markus Kuhn 12:08, 25 February 2006 (UTC)[reply]

Oppose. That German page isn't something to emulate, in fact it is a mess, basicaly a BNC page with a lot of stubs tacked on, about 23 of them all on one page. The RF connector page here does a better job of overview. The best response to stubs is not to merge them all into one megastub as in the German article but to add some content. Meggar 04:52, 30 December 2006 (UTC)[reply]
Oppose. I can see advantages in expanding the RF connector page to have a short description and perhaps a picture to help identification but there are many more connectors that can be included there so best to link to other pages for full details. --jmb 08:49, 30 December 2006 (UTC)[reply]

For what it's worth...[edit]

I'd like to put forth that I don't consider the Amphenol page 100.0% unbiased and therefore authoritative; it *was*, after all, their engineer; of *course* they'd say that. Oddly, the naming is a matter of some dispute, and I think we need a bit more backup on this... especially since Broadcast Engineering is using it as a quiz question this month. --Baylink 17:00, 29 December 2006 (UTC)[reply]

Video[edit]

I believe there was a convention in the BBC that 50 ohm BNC connectors were used on 75 ohm video circuits because the inner pin is more robust. I certainly only saw 75 ohm BNC connectors used on some older VHF receive antenna connection. There was also a two pin connector with an outer shell very much like a BNC, this was sometimes used for connecting balanced audio circuits. I don't know the name of the connector though, always referred to a "two pin BNC" even if not strictly accurate. --jmb 22:00, 29 December 2006 (UTC)[reply]

Uses[edit]

"The BNC connector is used for professional video connections, both for analog and Serial Digital Interface signals, amateur radio antenna connections, aviation electronics (avionics) and on nearly every piece of electronic test equipment manufactured in the last 35 or so years."

This reads as if it was started referring only to video uses then other uses have been added. Perhaps a more general summary of uses of the BNC would be better. Also the statement about electronic test equipment is not correct. N connectors are more common on much RF test equipment. --jmb 08:57, 10 July 2007 (UTC)[reply]
I've tidied the list up and reworded it slightly to make it more accurate (the test equipment statement having already been toned down). Musiconeologist (talk) 19:28, 15 August 2010 (UTC)[reply]

Uses continued[edit]

CCTV equiptment uses BNC —Preceding unsigned comment added by 86.16.160.17 (talk) 21:43, 9 March 2008 (UTC)[reply]

I haven't added this to the list since it seems to me to be covered by video signals in the first item.Musiconeologist (talk) 19:30, 15 August 2010 (UTC)[reply]

ambiguous picture[edit]

This article has a picture; the caption of that image reads "Picture to show the similarity between 50 Ω and 75 Ω BNC connectors". Ironically, the caption doesn't tell us which connectors in the picture are 75-ohm connectors, and which are 50-ohm connectors. Can anyone tell, and repair the caption? -- Mikeblas 00:22, 14 August 2007 (UTC)[reply]

If you go back to the description currently in the entry for this picture, it claims that all of these are 50 ohm. A 75 ohm connector has a slightly fatter center pin and a different (or different thickness) center dielectric. Also, the back of the connector must be different as RG58 (50 ohm) cable is significantly thinner than RG59 (75 ohm) cable. --ssd 05:57, 26 August 2007 (UTC)[reply]
Given no remedy, and because of the comments on the page for the picture itself, I've removed that image from this article. -- Mikeblas (talk) 01:15, 9 January 2008 (UTC)[reply]

Alternate image[edit]

Not an exemplary image. This connector probably conforms to the BNC standard, but with this super thin cable, it's not suitable for high frequencies, and might break easily. Robijn (talk) 11:40, 10 December 2017 (UTC)[reply]

Types[edit]

75 ohm BNC connectors are primarily used for video and DS3 Telco central office applications is ambiguous. Which of the following is intended?

  • Video and DS3 Telco central office applications primarily use 75 ohm BNC connectors.
  • The primary use of 75 ohm BNC connectors is for video and DSC3 Telco central office applications.

I think it needs editing into one or other of these versions.

Telco[edit]

Telco central office applications

  • Ambiguous because Telco has a number of meanings
  • Whole phrase needs clarifying
  • Once it's clear, it should be linked to whichever article is the relevant one.

BBC[edit]

The past-tense section about the BBC reads rather as though the BBC no longer exists, and could do with amending to say when the convention existed.

Musiconeologist (talk) 21:48, 18 August 2010 (UTC)[reply]

Origin[edit]

The basis for the development of the BNC connector was largely the work of Octavio M. Salati

I don't know what this statement is intended to mean:
  • Neill and Conselman's work was based on Salati's patent, and his work preceded theirs?
  • Neill and Conselman invented the BNC connector and then Salati helped develop it?
Anybody know?

Musiconeologist (talk) 19:59, 16 August 2010 (UTC)[reply]

British usage[edit]

I marked this section as dubious because:

  • currently it reads as though anything in the UK using a bayonet fitting would be described as having a BNC fitting. Clearly this is often not the case: for example I've never heard it used for bayonet-fitting lightbulbs.
  • Colloquial use of BNC fitting for other connectors doesn't necessarily mean it's accepted as correct British usage, so clarification is needed as to whether it is or not.

Musiconeologist (talk) 19:11, 15 August 2010 (UTC)[reply]

Electrical compatibility[edit]

I've kept the Canford Group reference for the statement about impedance mismatches, but I think a reference to a basic article about the theory of waveguides and tranmission lines, or to the relevant section of a textbook on that subject would be more appropriate---the effects are a matter of basic physics rather than a manufacturer's recommendations. Also the physics won't go out of date. Musiconeologist (talk) 19:18, 15 August 2010 (UTC)[reply]

Mechanical compatibility; IEC 169-8[edit]

I haven't managed to track down the text of IEC 169-8 online, but the references I have found suggest that it was explicitly for 50 ohm connectors. Presumably this includes specifying that their impedance should be 50 ohms, in which case a 75 ohm connector can't comply. If that's so, then a wording like whose physical dimensions match those specified in IEC 169-8 is needed, together with a footnote explaining that a 75 ohm connector can't technically comply with the standard.

Ideally a source for the text of IEC 169-8 should be cited. —Preceding unsigned comment added by Musiconeologist (talk • contribs) 19:47, 15 August 2010 (UTC)[reply]

It is a well known fact amongst radio technicians that the centre pin size of the 75 ohm and the 50 ohm types are minimally different. I cannot remember or find a source as to how this arose. The 50 ohm centre pin uses a larger form than the 75 ohm, as far as I'm aware. Using the wrong male connector will spread the centre contact in the female socket, however, when someone goes to use the correct plug, it will only make intermittent contact. Can someone back me up on this?, I need a credible source. Trumpy (talk) 03:56, 17 January 2011 (UTC)[reply]


86.201.68.118 (talk) 14:13, 6 April 2017 (UTC) I came onto Wiki to check dimensions as I am aware that 50 ohm and 75 ohm BNC are physically different. I have many times berated colleagues to keep them separate as the larger pin of the two will open up the smaller receptacle and ruin R.F performance for future coupling. It was a long time ago that I read the design details that specified the physical dimensions of coupling that defined the characteristic impedance.[reply]

I think that Canford's statement is mis-leading and only relates to their (mis-)use. "In over 15 years and many million BNC connectors we have no first hand experience of incompatibility between 50 ohm and 75 ohm types, other than extremely rare (and very obvious) manufacturing faults." 86.201.68.118 (talk) 14:13, 6 April 2017 (UTC) Radar-uk[reply]

It appears that the specification reference has been abbreviated from IEC 60169-8:1978 though I am unable to verify at http://www.iec.ch/dyn/www/f?p=103:38:14556868041568::::FSP_ORG_ID,FSP_APEX_PAGE,FSP_PROJECT_ID:1447,20,1520 — Preceding unsigned comment added by 86.201.68.118 (talk) 14:26, 6 April 2017 (UTC) Following my earlier observations I can shed some light on the confusion. Whilst it is true that the mechanical and physical construction determines the Characteristic Resistance it would appear that many modern 50/75 ohm BNC (AMphenol/Rosenberger - 11_Chapter_BNC_TNC.pdf et al) have managed to bring modern techniques to standardize their components by using dielectric padding as the medium of change: when looking into a 50 ohm BNC connector compared to a 75 ohm connector there is an obvious difference in dielectric thickness that does not preclude mating parts. Previous warnings are still valid as other (and older) cables are NOT compatible and in any case reflects on the user who is intending to mis-match and possibly cause problems for those following.[reply]

Naval connector?[edit]

I thought BNC stood for British Naval Connector, and have found other references to this including the reputable FOLDOC http://foldoc.org/bnc . Perhaps this should be reflected in the article?

There's lots of rumors and folklore about connector names - you'll often see "Baby N connector" and similar names made up by authors. Even FOLDOC is not flawless when it comes to minutia such as this. No-one has ever produced a British naval standard that defines this connector. --Wtshymanski (talk) 15:59, 7 December 2011 (UTC)[reply]
The article originally included a longish section listing a number of alternative names with their supposed etymologies---as I remember, this was eventually removed because of doubts about its relevance and its accuracy. It was more about how spurious names come into being than about the connector. Personally I think it would be a bad idea to bring it back, beyond maybe adding a sentence to the effect that confusion exists over the name and many spurious versions exist.Musiconeologist (talk) 01:16, 8 March 2012 (UTC)[reply]
To completely eliminate the mention of 'British Naval Connector' (in the discussion of etymology or otherwise) truly weakens the article.Opertinicy (talk) 05:22, 27 October 2012 (UTC)[reply]
It would be enlightening to have some sort of explanation of the origin of this etymology, rather than dismissing it as a backronym in a single sentence. --Ef80 (talk) 23:58, 14 August 2013 (UTC)[reply]
<years later> If it was a British name for this connector, surely it would be "Royal Navy Connector"? --Wtshymanski (talk) 01:09, 5 July 2022 (UTC)[reply]
If it was named by Brits I would say you are correct. If it was named for/after them by someone from another country, that is a different matter. (if that ever really was a name for it that is... Granted I remember being told to watch out for people calling them such in the earlier 00s when I was going to school for networking, repair and security stuff. Basically "if they say this, they mean that". So maybe it is worthy of mention?) Food for thought: Just because there is no actual standard from the UK that applies here does not invalidate the name per se. Ethernet was named after something literally proven to not exist (it became a standard later, but still, the name came first). 174.44.171.172 (talk) 21:11, 27 October 2022 (UTC)[reply]

BNC Origin?[edit]

I have worked on airborne radar for various British military aircraft, and the story that has filtered down by engineers from WW2 was that the BNC connector was 'invented' for the first centimetric radar the US ever had, the SCR-720, which was just a British A.I. mk. X set sent over to the States. To improve maintenance and reduce the time to change an aircraft's radar set, the USAF wanted a quick R.F. fit/release connector. Neill & Concelman (how is Concelman pronounced? Conkleman? Conselman?) originally came up with what is now the TNC (Threaded Neill Concelman) connector, arguing that it had a better frequency characteristic. However, they conceded that the bayonet means of fitment allowed for a quicker (dis)connection, so they came up with the BNC. However, they persisted with the TNC, and it is still available to this day.

Taff Hewitt (talk) 14:28, 20 May 2015 (UTC)[reply]

Baby Neil Constant[edit]

I found this patent dispute which gives quite a bit of info about the origin of BNC. It contradicts some of the details in the article. Below is Findings of Fact #13. Thoughts on including this? --mikeu talk 00:06, 24 April 2019 (UTC)[reply]

"The accused devices UG 88/U and UG 89/U are based upon a prototype developed by the Bell Telephone Laboratories and are part of a group generally known as the type BNC, which stand for Baby Neil Constant because they were originally designed as a small connector by Paul Neil of the Bell Telephone Laboratories and because they approached more closely a constant impedance device when used with 50 ohm cable at higher frequencies than the prior type BN connector. The differences are differences in degree and not basic differences in theory or design. The United States Government assigned the designations BNC, UG 88/U and UG 89/U to the Bell Laboratory connector in April, 1944, based on Bell Laboratory drawing ESL 662916, dated March 2, 1944 and the final Navy drawing of the connector is drawing RE 49F 246, dated December 2, 1944."[1]

I'll update the text given that there have been no objections. I just noticed a typo in the court document where Neill is misspelled Neil. I'll add an sic to the quote in the reference. --mikeu talk 20:06, 22 October 2019 (UTC)[reply]

The reference is unreliable given that it did not support the name as claimed. There is no requirement for a court document to be correct, only to support the plaintiff's or defendant's claims - and this one certainly wasn't correct. That is why it is unreliable. If we regarded every court document as reliable, Wikipedia would be filled with all sorts of whacky claims from the millions of patent disputes that clutter the American courts. The article BNC connector has reliable authoritative references for the correct name. 86.132.158.101 (talk) 18:46, 28 November 2019 (UTC)[reply]
Multiple reversions are not allowed per WP:3RR. Also, please follow WP:AGF or provide evidence of sockpuppetry. Thank you for coming here to discuss. I'll refer you to {{cite court}} which I used in the footnote. It is such a common practice to cite court cases that we have a template for that. The findings of fact are quite clear that they are based on contemporaneous witness testimony. All three expansions of the acronym are discussed together. You have not provided an alternative reference to support your contention. I'm going to return to the article to the original state until we reach a wider consensus. --mikeu talk 19:11, 28 November 2019 (UTC)[reply]
Also, the notice above was left in place for 6 months without objection before I made the change to the article. I would recommend that you follow similar caution when editing. --mikeu talk 19:14, 28 November 2019 (UTC)[reply]
This is a brand new expansion of "BNC" that I've never seen before. Lawyers are not RF engineers or dictionary compilers. --Wtshymanski (talk) 04:46, 29 November 2019 (UTC)[reply]
The problem with using court documents from civil disputes is that the disputants are under no obligation to tell the truth and are able to mislead the court if it helps their case. Unlike criminal cases, in civil disputes (and this includes patent disputes) there are no sanctions whatever for lying to the court beyond the judge taking it into account if it is proven before he passes judgement (nothing can happen afterwards). The subject document was most likely written by a lawyer, hardly an authority on R.F. connectors and definitely does not have the backing of a recognised authority on the subject. It fails WP:RS in the worst possible way.
I have never heard of ‘Baby Neill (or Neil) Constant’ for a BNC connector either and can find no reference to support it. Even Google returns nothing whatsoever, whereas there are thousands of hits for ‘Bayonet-Neill-Concelman’, though I did stop counting after the first ten pages. I suggest that you drop this. I think that you will find any attempt to hammer it into the article will be firmly resisted by many others.
The description would be inaccurate anyway, because the BNC is a 7 mm connector and thus a medium size connector. ‘Baby’ connectors would be the 3.5 mm size. Also the BNC is not a constant impedance connector. It is a lot closer than some others (and mostly adequate for the applications for which it is generally used) but has a long way to go compared with true constant impedance connectors. That is why it is the connector of choice for oscilloscopes even though the input impedance of the average oscilloscope is almost as far from 50 ohms as it is possible to get. 85.255.233.225 (talk) 13:56, 29 November 2019 (UTC)[reply]

I found this discussion yesterday afternoon after I had reverted the BNC connector name at Audio and video interfaces and connectors and decided to look into the matter further. I discovered that in early 1950 someone designed a miniature version of the N connector to produce a 3.5 millimetre version of the original. This was specified for use on a particular early 50's airborne radar system, which I believe to be one of the many H2S derivatives. There is no evidence in the documentation as to who designed it (person or company) so it may, or may not, have been Paul Neill. The connector was designated as a 'Baby N connector' or more often just 'Baby N'. From the photographs of the system, the female connector could easily be mistaken for a normal size N connector, but for scale which is difficult to judge in a photo with no other cues. The male connector was noticeably different but only in that the threaded part was hexagonal rather than knurled. It is clear that it was not a bayonet type connector. But for the presence of the extra screen and the size of the threaded parts, it is easy to visualise that this could have been the predecessor of the SMA connector which appeared about a decade later. There is no other coverage of the connector that I can find, so it seems to have had a very short availability (and it was probably obsoleted by the SMA which would have been considerably cheaper as it is much simpler in design).

I have since typing the above found a very few documents that talk about BNC connectors as 'baby N connector'. However, I also found an old 1955 document discussing various connector types and discussed (amongst others) about the baby N connector and the BNC connector as two distinctly different types noting that the baby N was a 3.5 millimetre format connector and that the BNC was a 7 millimetre format (which would fit as the full size N connector is 7 millimetre). All of these documents date from the 1950's. I can find no later dated documents that mention baby N connectors in either guise.

It would seem to me that in the 1950's that there was real confusion between the two connector names given the common initialism. The date of the patent litigation is 1958 so may well have been within the availability time frame of the baby N connector. The descriptions UG88/U and UG89/U do pertain to the BNC connector as we know it. Exactly who was confused over the expansion of BNC, we shall probably never know. Legal documents of this type pass through many hands, most of whom are not technical people so the opportunity for confusion of such matters is ever present. It is worth noting that the expansion of the initialism BNC is of no consequence to the patent dispute, so even if they had got it right, it still would not qualify as a reliable cite. -RFenergy (talk) 14:25, 30 November 2019 (UTC)[reply]

I propose this change to be reverted. As others have written before, this name is misleading, since the BNC is neither a baby, nor a constant impedance connector. According to Google and my personal experiences, most ham operators likely also know the BNC as "Bayonet Neill-Concelman", not as "Baby Neill Constant" (I, for one, have never heard of the latter). It seems it may have been confused with the baby N connector. However, as with the "British Naval Connector", this resolution could be added to BNC_connector#Origin. Bence98 (talk) 13:46, 7 December 2019 (UTC)[reply]

N connectors have screw threads. Surely a baby should resemble its parent? BNCs have no screw threads. --Wtshymanski (talk) 02:23, 10 December 2019 (UTC)[reply]
The Baby N connector did resemble the (parent) N connector. As I stated above, the only visible difference was that the threaded part of the male was knurled for the standard N and hexagonal for the baby N. This was the case for the illustrations that I have seen but it may not be universally true. The application that I have illustrations for would require individual connectors to be screwed and unscrewed with something resembling a tap spanner as they are quite densely packed. -RFenergy (talk)
Which change do you want reverted? The article was reverted to 'Bayonet Neill Concelman' on the 28 Nov and has not been touched since. Your post strongly suggests that you support the current version in which case you do not want a revert. -RFenergy (talk)
It seems you are correct. It might have been a cache mishap, that somehow caused me to see the older, incorrect version. Bence98 (talk) 19:28, 6 April 2020 (UTC)[reply]

"Baby Neill Constant" listed at Redirects for discussion[edit]

An editor has asked for a discussion to address the redirect Baby Neill Constant. Please participate in the redirect discussion if you wish to do so. signed, Rosguill talk 05:45, 21 December 2019 (UTC)[reply]

"Similar connectors" section twice?[edit]

It seems there are two "Similar connectors" sections (2. and 7. section, presently), one stating that similar connectors exist, the other listing them. This causes not only redundancy, but anchoring mishaps (linking to BNC connector#Similar connectors goes to the 2., BNC connector#Similar connectors_2 goes to the 7.). Is there a reason for it? If not, I propose them to be merged as such: the now 2. paragraph should be removed, its text placed at the top of the 7. paragraph, and BNC connector#Similar connectors linking to this, merged section. — Preceding unsigned comment added by Bence98 (talk • contribs) 20:07, 6 April 2020 (UTC)[reply]

Alright, merged them. Bence98 (talk) 23:06, 14 April 2020 (UTC)[reply]
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