I thought so too, until I tested* some supposedly 1500V transformers of the type used in NICs and found that they broke down at voltages a lot lower than 1500V (I think the lowest was 500V). Unless they are tested (and certified so), they may survive or they may emit smoke. Needless to say I rejected the batch. Now a faulty switch mode power supply could potentially put a lot more than 240V onto the "low voltage" output, as they switch at a much higher voltage internally, like 400 or 600 V. That would break down an uncertified NIC. Kaboom.
- Jill. * that was at Scitec many years ago. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, 7 December 2005 11:45 AM To: [email protected] Subject: [SLUG] Re: [ot] Using telephone wiring for networking? On Wednesday 07 December 2005 07:58, [EMAIL PROTECTED] wrote: > On Tuesday 06 December 2005 13:35, Robert Collins wrote: > > On Tue, 2005-12-06 at 10:41 +1100, James Gray wrote: > > > > AIUI austel certification only kicks in if you are connecting > > > > the thing to the phone network. If you happen to have a bunch of > > > > copper in the walls, that is not connected to the public network > > > > - it does not apply. > > > > > > And by "connected to the public network" they mean "in any way > > > through any device". So even if you isolate your network from the > > > public one with a router or modem etc, you're still deemed to be > > > "connected". Not sure if you're still deemed to be connected if > > > the external/public link is wireless though (they are more > > > concerned about electrical isolation than spurious data). > > > > > > At tleast this was how the regs were written back in '95 when I > > > was AUSTel Certified. Things may have changed - usual disclaimers > > > apply. > > > > Jesus thats scarey. Why isn't my power socket AUSTel certified ? > > Because the assumption is that you are using AUSTel approved > network/telephone equipment which has been certified to meet the > isolation requirements. > > I've personally seen what happens to a thin-ether (10base2) network > when a PC's power supply decided to send all 240VAC through the > motherboard and hence the network card. Goodnight Irene for > everything else too. However, the same machine had an AUSTel > certified internal (ISA) modem - the PABX it was running through was > untouched. > > See the difference? Ummmm ... when an elderly and distinguished scientist says something is impossible he's nearly always wrong ... A nic card has an isolating transformer rated to some 1000v between it and the cable. For the 240v to escape A it needs a faulty transformer on A, then to infect B it needs another faulty transformer on B .... James -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
