Re-wiring home phone lines

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GMW

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#55598 6-Jan-2010 19:45

Our home broadband service has ground to a halt because of increasing noise on our phone line. Over the past 18 months, our Internet access experienced worsening interuptions. Now it is almost impossible to access the Internet via the home modem and PC.

Our ISP slingshot has been booked to inspect the underhouse wiring (which an electrician warned several years ago was something of a messy DIY). Is an ISP the best option for rewiring (if needed). I understand the job would cost several hundred dollars. Who else does this type of work?

sbiddle

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#287560 6-Jan-2010 20:03

Is your homeline with Telecom or are you in a ULL area and have your internet and phone with Slingshot?

If you're with Telecom a Chorus tech will visit to check things - ISP's don't actually do anything themselves. If you pay line maintenance then they could fix any major issues for free. This won't necessarily extend to rewiring the whole house but could include replacing jackpoints and possibly include a central splitter.

There are plenty of electricians and data installers who would rewire things for you.

lapimate

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#287562 6-Jan-2010 20:14

GMW: the best option for rewiring ...

Instead, how about installing a cordless system for your 'phones with the filter and 'phone base-station at the Telecom Network Demarcation Point (ie the point where the Telecom cable is connected to your house cabling)? Then just the one cable to your ADSL modem.

sbiddle

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#287565 6-Jan-2010 20:20

lapimate:
GMW: the best option for rewiring ...

Instead, how about installing a cordless system for your 'phones with the filter and 'phone base-station at the Telecom Network Demarcation Point (ie the point where the Telecom cable is connected to your house cabling)? Then just the one cable to your ADSL modem.

Filters are still very much a "kludge". If you want the best ADSL/ADSL2+ performance a properly installed master splitter will virtually always deliver significantly better results.

CYaBro

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#287567 6-Jan-2010 20:28

I'm just busy rewiring our phone lines so I can move the ADSL router downstairs.
I can't even find a master splitter!
It seems to be wired quite differently to other houses I have seen.
I found the ETP, which is actually inside the house, and both pairs are being used on the incoming line (Black cable), one for the phone line and one for ADSL.
Is this a common way of doing things?

Opinions are my own and not the views of my employer.

lapimate

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#287577 6-Jan-2010 21:03

sbiddle: ... Filters are still very much a "kludge". If you want the best ADSL/ADSL2+ performance a properly installed master splitter will virtually always deliver significantly better results.

Thanks for the clarification. Is there actually anything electronically different between a "filter" (installed at the premises entry point) and a "master splitter"?

sbiddle

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#287581 6-Jan-2010 21:23

They both essentially do the same thing - they act as a low pass filter to split the ADSL and voice.

A master splitter however is of a higher quality and more importantly when installed close to the demarc point with a dedicated cable run just for ADSL ensures you're getting the best possible signal.

Most houses in NZ have jackpoints wired in series and to this day it still seems to very common for electricians in particular to do this yet Telecom have advised against doing this since the late 90's. Wiring in series can cause horrible problems with signal reflections which causes lower ADSL sync speeds.

cyril7

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#287705 7-Jan-2010 09:47

Thanks for the clarification. Is there actually anything electronically different between a "filter" (installed at the premises entry point) and a "master splitter"?

Just to clarify, the primary purpose of the filter or splitter is to isolate POTs devices from shorting out the DSL signal. The act of stopping DSL signals from upsetting POTs devices is a secondary result of the filter. POTs devices normally present a very low impedance (essentially a short circuit) at DSL frequencies and this can alter as they ring or go on or off hook. An ADSL filter (sometimes called a splitter) is an asymetric impedance filter that ensures that this effective short circuit impedance presented by the POTs device does not appear on the line where the DSL signal is.

I strongly recommend that a central filter is used rather than lots of inline filters at each phone point. If you have more than 4 inline filters across the line then the effective parallel impedance of all these filters can counter there effectiveness. If you have a alarm panel with back to base reporting then again you really have to have a central filter installed.

Only a central filter can side step the bad side effects of star wiring within your house phone wiring layout. Star wiring can cause reflections from each phone point that can destroy the DSL signal in a uncertain fashion, inline filters cannot assist with this issue, only a central filter normally installed at the ETP but can be installed anywhere in the line as long as it is installed on the direct inbound line that has no other phone points between it and the street and ideally a clean run of cat3 or greater run from the filter to a dedicated socket for the DSL modem.

Cheers
Cyril

*POTs , Plain Old Telephone service, ie voice band devices such as phones, fax modems, dialup modems, Sky STB modems, alarm modems etc.