Connecting a BT-style plug to an RJ45-style socket. Which adapter to use?

Forums › New Zealand Broadband › Connecting a BT-style plug to an RJ45-style socket. Which adapter to use?

bakery2k

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#65010 27-Jul-2010 19:49

I've recently moved into a new house in which there are a number of RJ45-style sockets, but no BT-style ones. The cables from the sockets all run to a central panel, where they meet a cable coming from outside. Currently the only connection on this panel is a blue pair of wires, connecting the cable from outside to a single socket. I presume this pair carries the standard telephone signals.

I have a standard telephone and an ADSL modem/router, both connected to a filter, which I'd like to plug into the appropriate RJ45 socket. Unfortunately the filter has a BT-style plug, so I am going to need an adapter.

Searching for adapters yields two kinds, one labelled "master" and the other unlabelled ("secondary"?). For example, at Dick Smith they have these two: http://search.dse.co.nz/search?w=rj45+bt

Which of these do I need?

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#357342 27-Jul-2010 19:56

Master if the phones need it to ring (rare now), secondary otherwise. No harm getting the master otherwise.

Richard rich.ms

bakery2k

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#357345 27-Jul-2010 20:02

Thanks.

So, if my phone is not one of those which must have a master adapter, either adapter will do?

What if in future I connect the blue pair of wires coming from outside to more sockets? Is it OK to use masters in all of them?

richms

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#357347 27-Jul-2010 20:16

Some it is, some it isnt, on some of them the ringer wire connects back onto the orange pair. That can stuff up the ballance on the line. I would just crimp up some RJ45 to RJ12 cables for the phones and abandon BT. Horrid plugs and IMO they should have been out the door instead of making the 2 wire versions.

Richard rich.ms

sbiddle

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#357364 27-Jul-2010 20:45

If you have no need for BT plugs just use RJ45 to RJ12 cables. These are the norm now for new housing installs where RJ45 is the recommended wall jack.

cyril7

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#357366 27-Jul-2010 20:47

If you have no need for BT plugs just use RJ45 to RJ12 cables. These are the norm now for new housing installs where RJ45 is the recommended wall jack.

+1, get rid of the BT, leave it to the wet on cold of blighty where it belongs.

Cyril

bakery2k

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#357446 27-Jul-2010 22:37

If you have no need for BT plugs...

Unfortunately my ADSL filter has a BT plug. Would you suggest replacing this instead of looking for an adapter for it? Are filters available which directly fit an RJ45 socket?

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richms

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#357449 27-Jul-2010 22:38

I would be more worried that you are installing the nasty hack of a plug in filter into a place with structured cabling in place

Richard rich.ms

bakery2k

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#357454 27-Jul-2010 22:40

Plug in filters are all I've ever used. What's the alternative?

richms

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#357456 27-Jul-2010 22:41

Splitter at the wiring panel and put the router there allowing jacks to be patched as voice or data as you choose.

Richard rich.ms

sbiddle

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#357522 28-Jul-2010 06:28

bakery2k: Plug in filters are all I've ever used. What's the alternative?

If you have a full structured cabling solution in your house your ADSL modem should be located with all the wiring and patch panel rather than being located next to a PC. This removes the need to have to install any splitters in the house.

Depending on how the wiring has been installed it may possibly have an ADSL master spiltter already. If it doesn't you can install a spiltter at this point and then connect the ADSL modem to one and then split the various ports to phones and data. Without knowing more about how things are installed it's hard to give any real advice.

old3eyes

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#357550 28-Jul-2010 08:45

cyril7:
If you have no need for BT plugs just use RJ45 to RJ12 cables. These are the norm now for new housing installs where RJ45 is the recommended wall jack.

+1, get rid of the BT, leave it to the wet on cold of blighty where it belongs.

Cyril

+1 as well. But unfortunately the ones in Telecom in the early 1990s who decided to retain the BT plug when they went two wire were poms so they followed where the empire went..

Regards,

Old3eyes

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bakery2k

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#357991 28-Jul-2010 22:12

Thanks for letting me know about the ADSL master splitter option - that does seem to be the way to go in the long term.

Meanwhile, however, I still need to connect a BT plug to an RJ45 socket, so I bought an adapter similar to this one:

http://www.dse.co.nz/dse.shop/4c50008300cef9f42742c0a87f3b06b6/Product/View/F9113

I was disappointed to find that this did not work. I feel that the adapter may be faulty, since:

1. The red wire from pin 4 of the RJ45 plug does not connect to any of the pins in the BT socket.
2. The green wire (RJ45 pin 5) connects to the pin in the socket closest to the latch (socket pin 2, corresponding to BT plug pin 5 - according to http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html) whereas my research suggests that it should connect to the pin furthest from the latch.

Is this simply a faulty adapter? Or have I picked up something intended for an entirely different purpose?

richms

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#357995 28-Jul-2010 22:28

pins 2 and 5 of the BT are the only ones that matter. Normally they go to 4 and 5 of the RJ45, but some I have seen use the second pair on 3 and 6, with the ringer wire connected to 4 or 5 (which ever order makes it a direct connection in order to the middle 4 of the BT.

Where are you? PM your street address and I can send you a PABX master. $14.95 for a cable like that at DSE is criminal IMO

Richard rich.ms

bakery2k

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#358002 28-Jul-2010 22:44

richms: pins 2 and 5 of the BT are the only ones that matter. Normally they go to 4 and 5 of the RJ45

That seems to be what this adapter is doing. Does it matter which of the two BT pins goes to which of the RJ45 pins, or can they be swapped?

The adapter I have seems to connect RJ45 pin 4 to BT socket pin 5, and RJ45 5 to BT socket 2. However, I believe it should instead have RJ45 4 to BT socket 2 and RJ45 5 to BT socket 5.

richms

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#358012 28-Jul-2010 23:01

polarity doesn't matter except for some strange caller ID issues.

Richard rich.ms

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