Return-Path: Received: (qmail 31939 invoked from network); 5 Dec 2002 13:03:50 -0000 Received: from murphys.services.quay.plus.net (212.159.14.225) by mailstore with SMTP; 5 Dec 2002 13:03:50 -0000 Received: (qmail 24223 invoked from network); 5 Dec 2002 13:04:22 -0000 Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 5 Dec 2002 13:04:22 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18JvfR-0007hT-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 05 Dec 2002 13:03:49 +0000 Received: from [194.247.47.231] (helo=mailout.zetnet.co.uk ident=mail) by post.thorcom.com with esmtp (Exim 4.10) id 18JvfQ-0007hK-00 for rsgb_lf_group@blacksheep.org; Thu, 05 Dec 2002 13:03:48 +0000 Received: from irwell.zetnet.co.uk ([194.247.47.48] helo=zetnet.co.uk) by mailout.zetnet.co.uk with esmtp (Exim 3.35 #1 (Debian)) id 18JvfQ-0001Zm-00 for ; Thu, 05 Dec 2002 13:03:48 +0000 Received: from a7j7r2 (bts-0721.dialup.zetnet.co.uk [194.247.50.209]) by zetnet.co.uk (8.11.3/8.11.3/Debian 8.11.2-1) with SMTP id gB5D3hO28098 for ; Thu, 5 Dec 2002 13:03:43 GMT Message-ID: <000101c29c5e$c1d64860$d132f7c2@a7j7r2> From: "John Rabson" To: rsgb_lf_group@blacksheep.org References: <036201c29bcc$641d4a30$0101a8c0@athlon> <3DEE6227.7060107@virgin.net> <5.2.0.9.0.20021204193347.00a8d3f8@pop2.sympatico.ca> Date: Thu, 5 Dec 2002 12:32:29 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: Re: Re: ADSL EMC with LF operation? Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-0.3 required=5.0tests=QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_00_01, USER_AGENT_OEversion=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group ----- Original Message ----- From: "Larry Kayser" > One final point, if you doing the ADSL setup yourself. The North American > ADSL/HDSL systems are largely line powered. It takes a major effort to > deliver 1W of DC to the far end of a long local loop so they regularly see > both sides of the 120VDC office battery for a total of nearly 250 V DC on > the loop from the central office. This can cause some very strong > reactions when ones fingers get into the stuff so if your doing it yourself > it is best to be careful, many of us have forgotten how to live with higher > voltages with all this 5 and 12 v stuff hi. If I recall correctly, UK practice was to run Strowger (TXS), reed-electronic (TXE) and crossbar (TXK) exchange equipment all off 50V dc. I do not know what later technologies such as System X used, but I believe there was a Health and Safety aspect which would tend to encourage the use of lower rather than higher voltages. Does anybody have more recent knowledge of this? Regards, John Rabson G3PAI