One rarely used but real application is where the DS3 coax is run between two adjacent central offices across an alley. This was the case in Chicago where the DS3 was a link between AT&T Long Lines and Illinois Bell. Because of possible ground loops the coax was grounded only at one end. Normally this would be a fiber link, but these things do happen occasionally.
Don -----Original Message----- From: Jon D. Curtis [mailto:j...@curtis-straus.com] Sent: Tuesday, June 13, 2000 8:34 AM To: nebs@world.std.com Subject: Re: DS3 Lightning DS-3 is also exempt for other reasons. Section 4.5 specifies application of surge and overvoltage to "paired-cable interfaces." Further the criteria of this section apply to "each telecommunications port connecting to an outside plant pair" DS3 is not a paired interface. They are discussed in section 4.6 which is entitled "Criteria for equipment interfacing with coaxial cable ports." This section replaces section 4.5 for coaxial cables. It also states "these criteria are not intended for... conventional telecommunications services, such as DS3." All this leaves DS3 without much of a home in section 4 of 1089. I would assume that the long duration of the deployment of DS3 has left the RBOCs with a good strategy of deployment of DS3 (adequate protection devices at the building entry) such that they are not experiencing problems with DS3, thus no additional regulation is needed. Until we get additional guidance from the RBOCs or Telcordia, it would seem the thing to do is to report when DS3 ports exist in a product so that future revisions of the product may be subject to requirements when, and if, they become necessary. I agree with Jim that if the DS3 stays within the building and the shield is connected to ground at both ends that no testing would be required under 4.5 (if you consider that applicable at all). I do however believe that DS3 may leave the building and that there exist implementations which do not ground the shield at one end. -Jon Curtis JIM WIESE wrote: > If both ends are intended to be grounded and you state this it in your > documentation, intra-building lightning is exempt on a DS-3. > > Jim > > Jim Wiese > NEBS Project Manager/Compliance Engineer > ADTRAN, INC. > 901 Explorer Blvd. > P.O. Box 140000 > Huntsville, AL 35814-4000 > 256-963-8431 > 256-963-8250 fax > jim.wi...@adtran.com > > > ---------- > > From: Joe Finlayson[SMTP:jfinlay...@telica.com] > > Reply To: nebs@world.std.com > > Sent: Monday, June 12, 2000 6:00 PM > > To: 'NEBS Newsgroup' > > Subject: DS3 Lightning > > > > > > I am hearing mixed opinions of whether a DS3 Coax interface falls > > under the scope of interfaces to be subjected to GR-1089 4.5.9 > > Intrabuilding > > Lightning Surge. The way I interpret the standard is that it does fall > > under the scope as there is no clear definition, that I could find, for > > "Telecommunications Port". I've seen verbiage citing examples, but no > > clear > > definition. This interface will not connect to outside plant and I do > > wish > > to claim shielded cables with grounds at both ends to avoid the testing. > > The scope of Section 4.6 clearly eliminates DS3 as part of that section. > > The program team is against testing it and I would not like to see a > > prospective customer reject the report. Any and all feedback and opinions > > from the group (RBOC's especially) would be greatly appreciated. > > > > Thx, > > > > > > Joe > > > > ********************************* > > <<...>> > > > > Joe Finlayson > > Manager, Compliance Engineering > > Telica, Inc. > > 734 Forest Street, Bldg. G, Suite 100 > > Marlboro, MA 01752 > > Tel: (508) 480-0909 x212 > > Fax: (508) 480-0922 > > Email: jfinlay...@telica.com > > Web: www.telica.com > > -- Jon D. Curtis, P.E. Director of Engineering Curtis-Straus LLC One Stop Laboratory for NEBS, EMC, Product Safety, and Telecom Testing. 527 Great Road Littleton, MA 01460 USA Voice 978-486-8880 Fax 978-486-8828 email: jcur...@curtis-straus.com WWW.CURTIS-STRAUS.COM