Kitz Forum

Broadband Related => Telephony Wiring + Equipment => Topic started by: b4z on March 17, 2018, 05:36:25 PM

Title: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: b4z on March 17, 2018, 05:36:25 PM
***Hypothetically Speaking***  :blush:

What are the implications of wiring the main line that comes into the house, directly to an RJ11 (64PC) plug and connecting that directly into the back of the (HG612) Modem?

It seems unnecessary that the line has to go through all the crap of master socket circuitry, faceplate circuitry, and all the filtering that involves etc. When all i want it as clean and clear as possible signal directly into the Modem.

[The line is never used for voice calls]

There is always the possibility that some of you more experienced/technical people maybe facepalming pretty hard right now.  ;D

Thanks!
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: underzone on March 17, 2018, 06:17:50 PM
I do that mate. An RJ11 is crimped onto the end of my dropwire. It should eliminate excess circuit loss/attenuation caused by the NTE.
Just keep the NTE handy so you can put it back on if you ever need to report a line fault  ;)
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: b4z on March 17, 2018, 07:26:41 PM
Could you tell me which of the 1/2/3/4 slots on the RJ11 plug, that the white and orange from the drop wire go into, when doing the crimping?  :)

Thanks!
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: underzone on March 17, 2018, 07:58:07 PM
The middle pair. So there is a 1 wire gap each side. Like this image (on the right):

(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww.tux-planet.fr%2Fpublic%2Fimages%2Fschemas%2Fprises%2Fnetwork-ports.png&hash=1da8271b94c193665777edae7dfd8b40)
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: Weaver on March 21, 2018, 10:58:49 PM
I'm with you. I have no filtering as there is no telephone. I use a faceplate converter plate that just turns the BT socket in the back part of the NTE5 master socket into an RJ45 socket ready for a cable to go straight into a modem.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: huwwatkins on March 22, 2018, 08:43:14 AM
Do you have a link to these faceplates?
Thanks

Edit - I think I've found them on AAISP shop but as I have two NTE5C's they are not compatible.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: sevenlayermuddle on March 22, 2018, 10:05:57 AM
It seems unnecessary that the line has to go through all the crap of master socket circuitry, faceplate circuitry, and all the filtering that involves etc.

Happy to stand corrected, but I believe the master socket components, ring capacitor & out of service resistor, as well as being necessary for ringing old phones, are also necessary for BT line testing to work.

If I am correct then without these components your broadband would work fine, but BT’s line tests might indicate a fault.

Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: tubaman on March 22, 2018, 01:03:10 PM
If the line has a speech circuit allocated to it then I would think you are correct.
I doubt the 1.8uF cap and 470k resistor across the circuit will make any noticeable difference.
I would use the standard NTE phone faceplate (ie no filtering) and just make-up a suitable lead to connect to the modem.
 :)

[Moderator edited to correct the mishap.]
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: burakkucat on March 22, 2018, 06:32:13 PM
Happy to stand corrected, but I believe the master socket components, ring capacitor & out of service resistor, as well as being necessary for ringing old phones, are also necessary for BT line testing to work.

If I am correct then without these components your broadband would work fine, but BT’s line tests might indicate a fault.

It is true that the shunt of the series connected 1.8uF capacitor and 470k resistor provides a "signature" as to what is present in the EU domain. If that signature has been recorded as present during previous automated testing, then its sudden absence would be "flagged up" as a potential circuit fault.  :-X

[Mishap corrected.]
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: sevenlayermuddle on March 22, 2018, 08:38:02 PM
470K resistor

470K resistor

I have never encountered such a resistor.  I have however encountered a resistor of 470,000 ohms, often referred to as 470k.

Couldn’t resist it, everybody likes a pedant, don’t they?   :blush:   :D

Genuine question -  given common usage of ‘k’ vs ‘K’ and my own pedantry,  would an actual 470K resistor be reasonably expected  to have a resistance of 481280 ohms?    ???
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: burakkucat on March 22, 2018, 08:49:18 PM
Genuine question -  given common usage of ‘k’ vs ‘K’ and my own pedantry,  would an actual 470K resistor be reasonably expected  to have a resistance of 481280 ohms?    ???

No, it would have a temperature of 470 K (where K is the SI unit of temperature, Kelvin).  :-[

[b*cat pads off to correct the inexactitude as a result of a momentary mishap.]
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: Black Sheep on March 22, 2018, 09:00:30 PM
It is true that the shunt of the series connected 1.8uF capacitor and 470k resistor provides a "signature" as to what is present in the EU domain. If that signature has been recorded as present during previous automated testing, then its sudden absence would be "flagged up" as a potential circuit fault.  :-X

[Mishap corrected.]

It would indeed, Mr cat.

It would show itself as a 'dis' (disconnection) on any remote line tests, performed by the CP/ISP.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: underzone on March 22, 2018, 09:39:54 PM
It probably wouldn't show as dis. (disconnected) when a modem/router is actually connected to the line.... This homehub 5 has the gas discharge and the DC block capacitor inbuilt, similar to an NTE5:

(https://abload.de/img/2015-05-1012.03.10kxufn.jpg)

Either way, the line will have -50V DC marking it as active, dial tone and also a VDSL signal present.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: Black Sheep on March 22, 2018, 09:53:57 PM
It probably wouldn't show as dis. (disconnected) when a modem/router is actually connected to the line.... This homehub 5 has the gas discharge and the DC block capacitor inbuilt, similar to an NTE5:

(https://abload.de/img/2015-05-1012.03.10kxufn.jpg)

Either way, the line will have -50V DC marking it as active, dial tone and also a VDSL signal present.

I couldn't comment on the Hub acting as an NTE, as I've never had that particular situation whilst faulting.

I don't know what is meant by your other comment though ?? All bog-standard VDSL broadband circuits will have those three symptoms you mention, present ............ it's whether those same three symptoms are reaching the end-users master socket, that matters.

The only way the CP/ISP's have to try and deduce this, is to run the remote test from the test-heads to the capacitor in the master socket.
It depends on what that test result returns, as to what the next stage of the fault process will be .... ie: appointed engineering visit or otherwise.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: burakkucat on March 22, 2018, 10:18:12 PM
.... This homehub 5 has the gas discharge and the DC block capacitor inbuilt, . . .

The over-voltage protection device, agreed, that is identical to the original NTE5/A.

However you are misinterpreting the capacitor, it is not part of a RC shunt across the pair but part of the high-pass filter. The high-pass filter blocks the low-frequency audio of the telephony service, and the baseband DC presence, whilst allowing the higher frequency xDSL signal through to the analogue front-end of the modem.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: sevenlayermuddle on March 22, 2018, 10:19:15 PM
It probably wouldn't show as dis. (disconnected) when a modem/router is actually connected to the line.... This homehub 5 has the gas discharge and the DC block capacitor inbuilt, similar to an NTE5

From cursory research, modem’s front end line interface seems to sometimes (/often/always?) comprise a tranformer, coupled by fairly low value caps, 0.1uF in circuits I have found.   The 470k resistor does not normally seem to be present.

Assuming that the line test uses a carefully chosen frequency, and looks for an impedance predicted by the correct cap/resistor combination, the modem connection would look quite different compared with the master socket’s R/C.

Not wanting to worry unduly but I’d imagine worst case scenario would be that BT, without prompting,  discovered such a “line fault”, and invested significant engineering resources in tracing it.   If the ‘fault’ were subsequently attributed to unauthorised tampering within NTE, I suspect they might quite reasonably want to recover full costs of investigation. :-X
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: gt94sss2 on March 22, 2018, 10:53:56 PM
What are the implications of wiring the main line that comes into the house, directly to an RJ11 (64PC) plug and connecting that directly into the back of the (HG612) Modem?

It seems unnecessary that the line has to go through all the crap of master socket circuitry, faceplate circuitry, and all the filtering that involves etc. When all i want it as clean and clear as possible signal directly into the Modem.

This is not my area of expertise by a long way but I always thought that Openreach FTTC faceplates (i.e. a Mk3) provided the unfiltered signal to the modem anyway - and it was only the voice socket that was filtered?

Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: sevenlayermuddle on March 22, 2018, 11:07:13 PM
This is not my area of expertise by a long way but I always thought that Openreach FTTC faceplates (i.e. a Mk3) provided the unfiltered signal to the modem anyway - and it was only the voice socket that was filtered?

That is true, but the components in question are not part of a filter.   Between them, capacitor and resistor, they provide ring signal and facilitate line tests.   Ring signal may no longer be relevant, but line test remains relevant.     

Filters (if needed) are an addition, over and above these components.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: 4candles on March 22, 2018, 11:10:23 PM
What you say is true gt94sss2, and I doubt whether the OP's proposal would give any measurable improvement in performance.
However, he has no requirement for telephony, so I can see some merit in ensuring a direct metallic path to obviate any possible problems due to component failure, dirty/corroded contacts etc.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: j0hn on March 22, 2018, 11:32:34 PM
I wouldn't crimp the incoming pair like that.
I don't use a landline, so went with an unfiltered faceplate.
£6 from AAISP
https://aa.net.uk/broadband-accessories.html
Just an RJ45 port on the front.

Only fits an NTE5A, not the newer NTE5C.
You couldn't pay me to install an NTE5C anyway. Hideous and flimsy.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: burakkucat on March 22, 2018, 11:55:31 PM
You couldn't pay me to install an NTE5C anyway. Hideous and flimsy.

I'll happily second that. The circuit, minimalistic as it is, just consists of lengths of steel plate made with slits into which the leads from the capacitor and resistor are forced. Like a third-world imitation of a IDC but one where there is no I to actually D!  :-X
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: tubaman on March 23, 2018, 08:37:38 AM
Sincerest apologies for my heinous misuse of a capital K (have I just done it again??).
Please send all claims for distress caused to my solicitor.
 ;)
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: adrianw on March 25, 2018, 02:55:29 AM
I don't use a landline, so went with an unfiltered faceplate.
£6 from AAISP
https://aa.net.uk/broadband-accessories.html
Plus £4.57 for Tracked 24 P&P.
Made my not very good line slightly worse, so I have gone back to a Mk 3 faceplate.
Presumably the Mk 3's anti REIN circuitry does something for me.

Impressively fast delivery. Ordered in the small hours of Friday morning, delivered on Saturday.
Title: Re: Master Socket wire wired directly to Modem via RJ11 ..?
Post by: Weaver on March 30, 2018, 08:19:43 AM
FYI those faceplates are available from the Andrews and Arnold shop at

    https://aa.net.uk/broadband-accessories.html

and you do not have to be an ISP-customer. (But you will have just to talk to humans sales@aa.net.uk about how you want to pay for goods if you don't have a customer account whose tab they can just add it on to.)