From owner-freebsd-hackers Sun Dec 19 23:43:56 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from ind.alcatel.com (postal.xylan.com [208.8.0.248]) by hub.freebsd.org (Postfix) with ESMTP id BD30714BCF for ; Sun, 19 Dec 1999 23:43:53 -0800 (PST) (envelope-from wes@softweyr.com) Received: from mailhub.xylan.com (mailhub [198.206.181.70]) by ind.alcatel.com (8.9.3+Sun/8.9.1 (ind.alcatel.com 3.0 [OUT])) with SMTP id XAA13298; Sun, 19 Dec 1999 23:43:21 -0800 (PST) X-Origination-Site: Received: from omni.xylan.com by mailhub.xylan.com (SMI-8.6/SMI-SVR4 (mailhub 2.1 [HUB])) id XAA01510; Sun, 19 Dec 1999 23:43:21 -0800 Received: from softweyr.com ([204.68.178.39]) by omni.xylan.com (4.1/SMI-4.1 (xylan engr [SPOOL])) id AA19510; Sun, 19 Dec 99 23:43:18 PST Message-Id: <385DDE7A.1A0ED466@softweyr.com> Date: Mon, 20 Dec 1999 00:44:58 -0700 From: Wes Peters Organization: Softweyr LLC X-Mailer: Mozilla 4.7 [en] (X11; U; FreeBSD 3.3-RELEASE i386) X-Accept-Language: en Mime-Version: 1.0 To: Matthew Dillon Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Cool little 100BaseTX switch - they're coming down in price References: <199912190410.UAA01049@apollo.backplane.com> <385C60FC.7613CB55@bellatlantic.net> <19991218225758.A23729@futuresouth.com> <199912190556.AAA08484@whizzo.transsys.com> <199912191943.LAA06826@apollo.backplane.com> <385D47D3.FCEE9EAB@softweyr.com> <199912192127.NAA09156@apollo.backplane.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Matthew Dillon wrote: > > :> I really hate these switching regulated DC wall plugs. They always use > :> cheap caps in them to save money and then don't bother adding any > :> protection to the motherboard. I prefer AC wall plugs or unregulated DC > :> wall plugs and then a small switching regulator on the motherboard. That > :> way you can throw anything up to 40V into it and it will still work. > : > :And nearly double the cost of the item, and make it much more difficult > :(read as "expensive") to pass FCC/EC requirements. You may prefer such > :things, but you're not willing to pay for them. (Generic "you" meaning > :"everyone" here). > > This is not true at all. Oh, and how many products have you passed through FCC/EC/Japanese environmental certification? None, apparently. > First, the U.L. is handled by the wall adapter. > Second, getting FCC certification for a small device whos U.L. is > arleady handled by a wall adapter is *trivial*. Right, becasue you don't have to certify the power supply, you just buy one that's already certified. If your "unit under test" requires 12vdc input, you can provide it with any form of 12vdc power you want. At our test facility, the most common is a car battery 200 ft away. The power supplies are often the hardest part to certify, and the major reason why most networking equipment is on FCC Class B certified, rather than Class A. For those of you who are wondering why this matters, it means it is illegal for you to use the equipment IN YOUR HOME anywhere in the USA if it interferes with any radio or TV reception anywhere. > Moving the switching > supply inside verses depending on a DC adapter does not make FCC cert. > more difficult. You're wrong. It nearly always requires adding some sort of faraday cage around the power supply, and often around the entire enclosure due to the difficulty in isolating the 60 Hz harmonics within the power supply in small equipment. For a small, cheap hub or switch this just kills the bill of materials. The Intel 8-port switch was already noisy enough they had to paint the inside of the case with copper spray; an internal power supply would have killed the product entirely due to the cost of the casing material. > There is an expense in the power supply verses the cheap crap you get > in a DC regulated wall adapter - well, doh! That's why it's better! Yup, and you'd be amazed the number of people that will buy the $99 switch over the $139 (or even $109) switch, even if they don't know the difference is the wall-wart. Other factors (like brand recognition) aside, that number is vanishingly close to "all of them." -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC wes@softweyr.com http://softweyr.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message