Line Fault - Internal House Wiring

[CharlieM]

Hi - I have recently moved to a house fitted with a NTE5a master socket, but none of the internal extensions in the house were live (no dial tone, nothing).  It appears that the house alarm system has been connected at terminals 2 & 5 and the internal extension wires had been disconnected.  Broadband and telephone are working properly through the master test socket and I am using a microfilter in the line.  I have connected the internal extension lines to terminals 2, 3 & 5 in the NTE5a and checked that the extension socket is also wired in the same way.  Since I have connected the extension I get a dial tone on both the main (connected directly to the master socket) and extension lines but when I dial I get the number unobtainable tone (whatever number I dial).  Any ideas about what could be wrong ?  Should I disconnect the alarm wires, pretty sure they're connected to the alarm but not critical to the operation of the alarm at present.  Thanks

[Keith_Beddoe]

@CharlieM 

Who provides your phone service?

[CharlieM]

BT.  Was Sky until I moved in.

[Keith_Beddoe]

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@CharlieM wrote:

BT.  Was Sky until I moved in.

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Make sure that you insert a microfilter in the lead to the phone, to filter out the broadband signal which is most likely stopping your phone from dialling out.

[CharlieM]

Hi Keith - I have a microfilter in both the 'main' and extension lines.  

[Keith_Beddoe]

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@CharlieM wrote:

Hi Keith - I have a microfilter in both the 'main' and extension lines.  

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Provider the extensions are connect to the correct point on the NTE, then it should be fine.

You may be better to fit a MK4 filtered faceplace, that would save using a microfilter on the master socket. It may also be worth temporarily removing the wires to the alarm, just in case the alarm is corrupting the DTMF tones from the phone. I assume you do have the phone set to tone dialling?

https://www.openreach.co.uk/orpg/home/helpandsupport/how-toguides/howtoguides/downloads/NTE5C_Instru...

Have you made sure that your phone has changed from Sky to BT Retail? What do you get when you dial 150?

[CharlieM]

Hi Keith - The phone is set up for tone dialling and is connected to BT.  Everything works fine (phone and Broadband) when plugged into the test socket (through a filter).  It is only when the extension (and the cable to the house alarm system) is connected to the faceplate and handsets are connected (through a filter) through the external socket and extension socket that I get the problem.  This points toward a problem with the alarm connection but I'd like to understand why that might be before disconnecting the alarm from the faceplate.  Think I might just have to go ahead and disconnect the alarm and see what happens (I'll power down (battery and mains) the alarm first !).  Thanks for your suggestions.

[Keith_Beddoe · Accepted solution]

I assume the alarm connection also has some form of filter to block the broadband signal?

It possible that the alarm unit is reducing the level of the tones that are sent out by the phone, when you dial out?

You do not need connection 3 on extension wiring any more, only 2 and 5. Leaving 3 connected can unbalance the line, and may affect your broadband speed.

Also if the extension sockets are of the wrong type, and are master sockets instead, then the extra components in those master sockets, can reduce the level of the audio.

[CharlieM]

Hi Keith - disconnected the alarm line and problem remained; disconnected line at terminal 3 on master and everything works, no problem.  Thanks for your help.

[Keith_Beddoe]

Excellent 😀

Terminal 3 has not been required for a long time now. It was used when phones had mechanical bells inside, and the wire was used to provide the link from the internal capacitor in the master socket. That capacitor can affect the audio level, as in your case.