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Standard User Ancient_Mariner
(eat-sleep-adslguide) Thu 11-Feb-21 14:43:27
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Useless? BT431A plug to RJ11 socket Adaptor


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Readying to test my new VoIP Adaptor (Cisco ATA191), I used a brand new BT431A Plug to RJ11 Socket adaptor.from a sealed packet. Only to find that internally, the two centre wires of the RJ11 (Red & Green) were NOT connected to pins 2 & 5 of the BT431A, but instead to pins 4 & 3 of the BT431A ("Earth" and "Bell Wire"".

In other words it was a straight through connection.

What use would such a connection be used for? Certainly not a 2-wire phone or a MODEM.

Would not be so bad, but I think that I have another one of the same make in my box of connectors.... crazy

Clive

Andrews & Arnold Home::1 FTTC DrayTek Vigor 2762ac Cisco SPA112 and HUAWEI E5776 with O2 Data SIM
Standard User copex
(committed) Thu 11-Feb-21 20:50:34
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Re: Useless? BT431A plug to RJ11 socket Adaptor


[re: Ancient_Mariner] [link to this post]
 
the lead is correct, some fax's / modems / phones use straight through cables.

though EU connectors are more common and the line is on the centre pins, this is more logical when you understand we are the only country that use the white connector, USA use rj11 to rj11 and EU use rj11 to rj11 with the addition of a local adaptor.

google RJ11 to BT Plug 2 Wire Crossover and you should find what you are looking for smile
Standard User Michael_Chare
(fountain of knowledge) Thu 11-Feb-21 21:39:24
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Re: Useless? BT431A plug to RJ11 socket Adaptor


[re: Ancient_Mariner] [link to this post]
 
In reply to a post by Ancient_Mariner:
What use would such a connection be used for? Certainly not a 2-wire phone or a MODE .
My phone and modem cables were not interchangeable. One used pins 3 and 4 the other used pins 2 and 5 of the RJ11 plugs.

Michael Chare


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Standard User MHC
(sensei) Thu 11-Feb-21 21:57:15
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Re: Useless? BT431A plug to RJ11 socket Adaptor


[re: copex] [link to this post]
 
In reply to a post by copex:
the lead is correct, some fax's / modems / phones use straight through cables.

though EU connectors are more common and the line is on the centre pins, this is more logical when you understand we are the only country that use the white connector, USA use rj11 to rj11 and EU use rj11 to rj11 with the addition of a local adaptor.

google RJ11 to BT Plug 2 Wire Crossover and you should find what you are looking for smile


There are many other countries where the BT style (BS6312) are still used - New Zealand, Nigeria, Ghana, Zimbabwe, UAE, Saudi Arabia, Hong Kong, several other African countries, middle East ... Most are slowly moving to RJ11 style, but the BT connectors are still plentiful.


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M H C


taurus excreta cerebrum vincit
Standard User MHC
(sensei) Fri 12-Feb-21 10:35:19
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Re: Useless? BT431A plug to RJ11 socket Adaptor


[re: Ancient_Mariner] [link to this post]
 
Have you sorted one yet?


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M H C


taurus excreta cerebrum vincit
Standard User Ancient_Mariner
(eat-sleep-adslguide) Fri 12-Feb-21 11:05:43
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Re: Useless? BT431A plug to RJ11 socket Adaptor


[re: MHC] [link to this post]
 
Initially thought I had bought a dud, carefully opened it out and could see it was a straight through connection which I knew was wrong. I have wired a few phone systems etc and became curious as to its true purpose. When looking up the possibilities, I was reminded that due some quirk in a specification somewhere, the numbering of a BT431A plug, is the opposite way round to a BT431A socket... ie pin 2 of the plug goes into pin 5 on the socket.

That all said, when I came to set up the Adaptor I used a correctly wired RJ11 converter which has a BT431A socket and ring capacitor. It is only needed for finding the Adaptor's IP address and final tests.

Cheers!

Clive

Andrews & Arnold Home::1 FTTC DrayTek Vigor 2762ac Cisco SPA112 and HUAWEI E5776 with O2 Data SIM
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