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Thread: Phones to Structured wiring Q

  1. #1
    Automated Home Jr Member
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    Default Phones to Structured wiring Q

    Completed my CAT 5 terminations T568B (ignore DSL side of things for this post)

    I have ‘paralleled’ off a number of ways as per the helpful picture posted here, so as long as I plug my filtered POTS feed into one ‘way’ I can patch out from the other ‘paralleled’ ways to any of the outgoing ‘ways’ on normal panels to room outlets.

    Intend following advice given here to patch across only 2 & 5 from the filtered side of the NTE5 to the CAT5 patch panels, and then use PABX master LAU at each faceplate outlet where I want phones.

    This is to avoid any issue with the Microfilter not providing enough REN - each LAU having it’s own capacitor.

    I could play about until it works, but does anybody know what connections on a RJ45 plug I need to connect the POTS ? to the CAT 5 at the ‘feed in’ point.

    The LAU’s show that it has phone across 2 and 5 of the BT socket (normal) and these connect to pins 5 & 4 respectively on the RJ45 plug.
    The capacitor is connected across pins 5 & 4 of the BT socket.

    This is the bit where it is slightly confusing as the capacitor is normally across 2 & 3 ?


    So does that mean standard phones with BT 431 plugs pre-wired will not work ? as they will expect ringing on 3 and it will be on 4

  2. #2
    Moderator toscal's Avatar
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    The quickest way to get this to work, I think is to buy a BT to RJ45 adapter.
    Maplin sell them. http://www.maplin.co.uk/module.aspx?...&doy=24m2#spec
    Also Krone make a version of these as well.
    Some usefull links for you to look at.
    UK telephone systems
    http://www.wppltd.demon.co.uk/WPP/Wi...telephone.html

    RJ45 and telephone stuff
    http://yoda.uvi.edu/InfoTech/rj45.htm

  3. #3
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    Quote Originally Posted by toscal View Post
    The quickest way to get this to work, I think is to buy a BT to RJ45 adapter.
    Maplin sell them. http://www.maplin.co.uk/module.aspx?...&doy=24m2#spec
    Also Krone make a version of these as well.
    Some usefull links for you to look at.
    UK telephone systems
    http://www.wppltd.demon.co.uk/WPP/Wi...telephone.html

    RJ45 and telephone stuff
    http://yoda.uvi.edu/InfoTech/rj45.htm
    You have misunderstood ... I have already bought RJ45 to BT adapaters ... they are the LAU master PBX detailed in the post
    i.e. http://www.molexpn.co.uk/products/pdf/AAA.pdf

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    Automated Home Legend TimH's Avatar
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    Quote Originally Posted by osprey View Post
    Intend following advice given here to patch across only 2 & 5 from the filtered side of the NTE5 to the CAT5 patch panels, and then use PABX master LAU at each faceplate outlet where I want phones.

    This is to avoid any issue with the Microfilter not providing enough REN - each LAU having it’s own capacitor.
    Usually you only have one Master socket in a given system and your new NTE5 will provide that. The usual way is to then wire the subsequent phone sockets as "Secondary"s. Wiring out extensions using master sockets with all of the components still in them can lead to problems and unless you have a special situation, you're better off using secondary ones.

    How many phones/devices are you thinking of using? REN dates from the days when phones had real bells in them and took "significant" current to make them ring. Modern phones don't need nearly as much juice so although the REN limit is 4 (IIRC) and you modern phone will be REN 1, in reality it is probably much lower than that. Manufacturers can't quote REN values less than 1 however.

    After commissioning, if you find you have a REN problem, the simplest solution is a box like this:
    http://cpc.farnell.com/jsp/endecaSea...sp?SKU=TE03562 (click the "Catalogue Page" link on the right hand side for more info)
    This raises the REN "capacity" from 4 to 11.

    As for the pinouts, this thread should have all you need:
    http://www.automatedhome.co.uk/vbull...read.php?t=534

    HTH,

    Tim.

  5. #5
    Automated Home Guru vex's Avatar
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    Pins 2 and 5 on the BT side carry voice, and these are typically the blue pair.

    Hence why they are matched across to 4 & 5 on the RJ45 side. What you have described should be fine and works every time for us and our installers. Although you will still be limited to a REN of four as (iirc) it is the power down the line from BT that is the limiting factor rather than the microfilter or the NTU.

    With what looks like the capacitor across pins 5 & 4, r u sure you have the plug / socket up the right way? if you turn it over the pins transpose on to 2 & 3.

    BT plugs are a nightmare because very few people publish where pin one starts and which side the lock/latch should be.

    I thought it always should be top left, like computer chips, put resently I have struggled to get this to follow.

    Katman should be along shortly to explain, deride, correct me.
    www.intouchtech.co.uk (trade)
    NOW PART OF INVISION UK, One of the leading home technology distributors to the CI Market.

  6. #6
    Automated Home Legend TimH's Avatar
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    Quote Originally Posted by vex View Post
    BT plugs are a nightmare because very few people publish where pin one starts and which side the lock/latch should be.
    From the link in my previous post, there's this message which clarifies:
    http://www.automatedhome.co.uk/vbull...2&postcount=11
    BT1 is nearest the tag so looking at the plug with the tag on the right it goes 654321
    HTH,

    Tim.

  7. #7
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    Quote Originally Posted by TimH View Post
    Usually you only have one Master socket in a given system and your new NTE5 will provide that. The usual way is to then wire the subsequent phone sockets as "Secondary"s. Wiring out extensions using master sockets with all of the components still in them can lead to problems and unless you have a special situation, you're better off using secondary ones.

    How many phones/devices are you thinking of using? REN dates from the days when phones had real bells in them and took "significant" current to make them ring. Modern phones don't need nearly as much juice so although the REN limit is 4 (IIRC) and you modern phone will be REN 1, in reality it is probably much lower than that. Manufacturers can't quote REN values less than 1 however.

    After commissioning, if you find you have a REN problem, the simplest solution is a box like this:
    http://cpc.farnell.com/jsp/endecaSea...sp?SKU=TE03562 (click the "Catalogue Page" link on the right hand side for more info)
    This raises the REN "capacity" from 4 to 11.

    As for the pinouts, this thread should have all you need:
    http://www.automatedhome.co.uk/vbull...read.php?t=534

    HTH,

    Tim.


    Tim ...
    Not using secondary - using RJ45 outlets (no components) and LAU pbx master adapters.
    Advice I had from several guys was that a standard single microfilter can limit the REN capability once you start having a lot of AC ringning current going through the single capacitor.
    The advice was from the NTE5 - obvioulsy patch A&B to my DSL Modem, but only connec2&5 across the the commoned ways on the'voice' patch panel.

    This means only 2&5 patched then to each faceplate outlet - in order to generate ringing at each outlet you then use PBX master LAU .... which are RJ45 to BTsocket, and on this version also has a standard capacitor to generate ringing.
    .. this is the normal way an office would be wired.

    I have sourced the PBX Master LAU ... just concerned/confused how the ringing that they then create onto pin4 will alllow standard phones to work which look for ringing on pin 3 ?

  8. #8

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    Quote Originally Posted by osprey View Post
    I have sourced the PBX Master LAU ... just concerned/confused how the ringing that they then create onto pin4 will alllow standard phones to work which look for ringing on pin 3 ?
    Simple answer is that if the ringing is presented to Pin 4 the phones will not ring unless they are phones that only use 2 wires.

    Pin3 of the BT socket is the ringing wire irrespective of whether it is a normal exchange line or an analogue PBX extension.

    Pin4 of the BT socket is used for a signalling earth on PBXs that use Earth Recall as opposed to Timed Break Recall.

    Pin 1 is adjacent to the latch on the BT Plug.

    Hope that helps.

    Keith
    KAT5.tv - affordable high quality AV Distribution
    http://www.kat5.tv

  9. #9
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    Quote Originally Posted by katman View Post
    Simple answer is that if the ringing is presented to Pin 4 the phones will not ring unless they are phones that only use 2 wires.

    Pin3 of the BT socket is the ringing wire irrespective of whether it is a normal exchange line or an analogue PBX extension.


    Keith
    Thanks Keith ..

    I think the Tech sheet of the manufacturer was mixing up BT socket & plug numbering ...
    I finished my CAT 5 termination today and all works perfectly.

    For ease of use I have created 2 new 'NTE5 masters' in Node zero ... used a pre-installed piece of CAT5 to do this from the BT demarc point.
    Did this so - in the event of any line issues I can simply pull off lower half front plates of NTE5 to isolate house from lines.
    To avoid any test issues I removed the Out-of-Service resistors from these 'new' NTE5's ...
    I just connected A+B legs between the BT NTE5's and my own.

    I then connected A+B on my phone only line to Patch panels (2 & 5 on NTE5 to B & A resp) made sure I had
    -48V on B.

    The PBX master LAU then generates the local ringing via in-built capacitor.


    On the 2nd line - I used a Clarity micro filter faceplate, I again distributed only filtered POTS (2 & 5) to the voice patch panel, and A&B to my DSL router.

    Glad to say all working fine.

    I was pretty pleased out of 32 terminated sockets only one did not test properly with LAN tester ... that had a bad connection on one pin on the outlet.

  10. #10
    Automated Home Legend TimH's Avatar
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    Quote Originally Posted by osprey View Post
    Tim ...
    Not using secondary - using RJ45 outlets (no components) and LAU pbx master adapters.
    Advice I had from several guys was that a standard single microfilter can limit the REN capability once you start having a lot of AC ringning current going through the single capacitor.
    The advice was from the NTE5 - obvioulsy patch A&B to my DSL Modem, but only connec2&5 across the the commoned ways on the'voice' patch panel.
    Did you get this info from another forum, or by PM? If it was another forum can you post the link - i'd be interested to read-up some more.

    Thanks,

    Tim.
    (p.s. glad it's all working for you now)

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