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[waltergmw]

Hello Gentlefolk,

I was trawling the web for a "proper" screened modem lead and came across:-

www.itm-components.co.uk

who are selling a US / Chinese product sold in the US by L-com.com Global Connectivity.

This lead has partly metal-clad RJ11 connectors so, if you have a better engineered modem such as a 2Wire with a metal contact in the RJ11 socket, you will have a screened and earthed lead. Those with domestic grade routers such as Thompson, Netgear or Linksys could achieve the same by carefully soldering an earth lead tail on to it.

Kind regards,
Walter

[roseway]

Mybe I'm being dim, Walter, but I'm having difficulty finding the product you describe on that site. Could you provide a link to the page?

[HPsauce]

Screened AND earthed leads can be a nightmare for the uninitiated.
You need to be very careful not to create any earth loops, this is really a job for professional installers.

Best to stick to conventional stuff, the best SSTP RJ11 cables will probably give a better result anyway - as sold by ADSLnation and others. 

[waltergmw]

Here's the link:-

http://www.itm-components.co.uk/iqs/cpti.466/dbitemid.602/sfa.view/telecoms_modular_cat5e_shielded.html

I agree with HP re difficulties, many of which stem from earthing both ends. However the ADSLnation filter face plate or dongle filter don't have any metal so you avoid that problem.  Next time I have a chance I'll experiment for us.

Kind regards,
Walter

[roseway]

>> Here's the link:-

Thanks Walter.

[orainsear]

If you can get hold of those RJ11 connectors and a decent crimp tool you could make up your own cables if you use something like the ADSL Nation Pro + Braided cable.

It's easy to bond to your mains earth with the Business Hub because of the continuity between the metal plating around the sockets/metal casing and the earth pin of the transformer, so in essence you have a large earthed Faraday cage.

However aren't most other modem/router transformers two pin double insulated so there is no easy path to bond to earth?

[waltergmw]

@ Orainsear,

I think your description of the screen bonding to the Faraday cage is correct but all modem PSUs I've come across whether 2 or 3 mains pins and including the 2 Wire one, only have a two conductor plug for the modem. On the 2Wire modem the Faraday cage is connected to the cable screens, the outer DC power pin and the mains earth pin. The connection diagram shows is a negative ground. However the only other PSU I have available from a Netgear DG834V4 is a transformer type with the same negative earth symbol diagram but the metal mains earth pin is NOT connected to the DC plug outer pin. That doesnt really matter, except perhaps to the standards inspectorates, as the modem has an all plastic case.

It follows that anybody with several modems and PSUs should ensure they are not swopped even if they are the same voltage.

I have also noted that both RJ 11 plugs have the drain wire soldered to the metal shroud so that could potentially produce an screen/ground loop IF both devices have shrouded RJ 11 sockets.
However I suspect all UK filter faceplates and filter dongles have plastic sockets rather than shrouded ones.

Just for completness the cable that L-Com use is 4 core 26 AWG Cat5e FTP into 6 pin RJ 11s with the innermost uncrossed pair using the blue pair, the next using the uncrossed orange pair and the two outer pins left unconnected.

Kind regards,
Walter