[VoIP] Channel Bank on Ebay [not mine] and E&M

Sat Dec 8 02:14:51 CST 2007

Steph,

I hear what you say and I understand it too but I have to say that the 
confusion is most likely due to the use of the word 'jack', I actually 
think it was a poor choice to create a standard called Reference Jack  
when it might better have been called something else that would not be 
so easily misinterpreted.

I think the problem is that many of us assoicate the word jack with 
socket and particularly in telephone work in the UK jack is the 
preferred word i.e. battery jack, line jack etc referring to a physical 
device.  Of course since the 1980s we have come to know the telephone 
plug and socket almost universally, prior to that very few subscribers 
had sockets but we booked them out of stores as Jacks 95A or similar.

You are correct in that we would not say RS232 Plug, I would've simply 
said serial plug which isn't correct today but it was all we knew a DB25 
for at one time and these things do stick. 

Now you mention the use of modular jacks but I don't recall seeing the 
word 'modular' mentioned anywhere on the URL that Arthur posted, indeed 
the standard makes no mention of the physical at all except for one 
entry where weatherproof is mentioned so many of these standards could 
apparently be used on all sorts of connectors. You say the codes 
identify 'jacks', and your point regarding plugs is perfectly clear,  
but I can see all sorts of connector sockets fitting the bill for a jack!

Brian

Steph Kerman wrote:
> I think what John meant is that RJ codes refer to Registered Jacks.  
> Therefore a plug crimping tool by definition can not "do" *any* RJ 
> code.  It can "do" plugs that mate with particular RJ codes but not "do" 
> the codes themselves as stated since the codes identify jacks. 
>
> Perhaps this is a finer semantic distinction than some would care to 
> make but I believe it is what he meant and the point is valid since the 
> misstatement perpetuates or masks a misunderstanding of what the RJ 
> codes mean... that they identify a type of plug or jack the way "DB25" 
> does.  They identify an electrical interface to the PSTN which has a 
> defined mechanical configuration more akin to the way RS-232 does.  Just 
> as one would not say "RS-232 plug" referring to a DB25 or DE9, it's a 
> misnomer to use RJ codes to refer to the plugs and jacks. 
>
> AFAIK, RJ10 is just another figment of someone's imagination.  It's not 
> listed in my 1997 Code of Federal Regulations "FCC Part 68" document nor 
> in my 1980 Bell System Registration Service Manual.  I've never heard of 
> it.  I know of only one RJ definition that has been added and is not 
> shown there: RJ61 provides access to 4 CO lines on an 8 position jack.
>
> R12 and RJ13 provide access to a CO line terminating in a Bell System 
> 1A2 key telephone system.  They provide access to the speech path along 
> with A leads (control leads towards the KTS to light the lights, stop 
> incoming ringing and clear a hold condition).  One of them provides the 
> speech path access on the CO input side of the KTS CO line circuit.  The 
> other provides it on the output (KTS telephone set side) of the KTS CO 
> line circuit.  Part 68 will identify which is which.  They all terminate 
> on a 6 position 4 or 6 contact modular jack with 4 contacts in use and 
> require a mating 6 pos 4 or 6 contact plug.
>
> There are no RJs associated with 4 position handset jacks.  Likewise, 
> the jack on a telephone set by definition can not be an RJ though it may 
> have compatible contact assignments and mechanical characteristics.  I 
> explained the reasons why this is so within the last 48 hours.
>
> Steph
>
> John Novack wrote:
>   
>> Repeating a previous post.
>> Handset plugs and jacks HAVE NO RJ designation.
>> All Rj designations refer to the wiring pattern and connections starting 
>> back in 1978.
>> Refer to FCC  Part 68 BEFORE 2000.
>> Google should be your friend.
>> RJ 12 and 13 reference connections to 1A2 key systems, RJ14 is 2 lines on one jack, RJ-25 is three lines on one 6 pin jack.
>> RJ3x and 4x are 8 position modular .
>>
>> John Novack
>>
>>
>> windmill wrote:
>>   
>>     
>>> Steph,
>>>
>>> Perhaps you can clarify what RJ10 and RJ12 are, I had always thought the 
>>> RJ12 to be a telephone handset plug but I have never really known what 
>>> an RJ10 is. My Crimping pliers do RJ45 (8P8C), RJ11 (6P6C) and a 4P4C 
>>> connector which I believe is RJ12. I have seen a two pin version in this 
>>> same series used internally in some telephones, would that be RJ10?
>>>
>>> Brian
>>>
>>> Steph Kerman wrote:
>>>   
>>>     
>>>       
>>>> Thanks for the clarification. 
>>>>
>>>> That has to be a moniker that someone invented, in other words, sort of 
>>>> a fiction.  It has no real legitimacy no matter how many people may use 
>>>> it, the way RJ11 and most others do.  Many people also refer to the 
>>>> handset jack as an RJ22, another mis-invention in this case since the 
>>>> RJ22 actually is a documented and defined interface that uses a 25 pair 
>>>> Amphenol mini-ribbon connector to connect to multiple lines.
>>>>
>>>> Regardless of its popular use, RJ has a formal meaning.  It refers to a 
>>>> "registered jack" under the FCC program that was established to allow 
>>>> direct connection of privately owned equipment to the public network.  
>>>> Since the Bell System was never forced by the FCC to allow connection of 
>>>> privately owned equipment to their own phones at the handset interface 
>>>> (as opposed to directly to the line itself), no RJ was ever defined 
>>>> using the 4-position jack.
>>>>
>>>> Steph
>>>>
>>>> Mark Rudholm wrote:
>>>>   
>>>>     
>>>>       
>>>>         
>>>>> RJ9 is the small (four conductor positions) connector
>>>>> used on handsets and handset cords.
>>>>>
>>>>> (it's not normally used for phone lines, with some
>>>>> weird exceptions, like Sangoma FXS PCI cards)
>>>>>       
>>>>>         
>>>>>           
>>>>>>>   
>>>>>>>
>>>>>>>         
>>>>>>>           
>>>>>>>             
>>>>>>>               
>>>>   
>>>>     
>>>>       
>>>>         
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>>     
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