Re: Is Zone Alarm necessary with a DSL firewall?
- From: "bud--" <budnews@xxxxxxx>
- Date: 10 Nov 2006 08:18:21 -0800
On Nov 10, 7:11 am, "w_tom" <w_t...@xxxxxxx> wrote:
DanS wrote:
Many people don't realize that a quality UPS, not necessarily a huge one,battery backup mode. Where is power conditioning? It does not exist.
just not a super-cheapy, have benefits beyond poer backup. They will
protect as a surge protector as well as act as a line 'conditioner'. You
know, like the $150 Monster surge protector/conditioners they try to sell
you when you by a flat panel TV. ... The plug-in UPS connects AC mains directly to electronics when not in
A relay does not 'condition' electricity. When does that electronics
see most 'dirty' electricity? When UPS is in battery backup mode. For
example, this UPS outputs as 120 volts: two 200 volt square waves with
a spike of up to 270 volts between those square waves. AC mains
provide 120 V sine wave and no spikes; much 'cleaner'. UPS in
battery backup mode outputs a waveform so 'dirty' as to even damage
some small electric motors. But computers are so robust that a 200
volt square wave and spike does no harm.
They are called 'computer grade' UPSes. So where is this power
conditioning? UPS provides 'cleanest' power when relay connects
electronics directly to AC mains. Where is this power conditioning?
Well where are its numerical specifications that claim such
conditioning? UPS numerical specifications 'forget' provide
numbers such as THD. Rumors claim 'power conditioning' that is
not in that numerical spec sheet.
If a surge protector is listed under UL 1449 it has MOVs from H-N,
Where is surge protection? Well it does provide protection from one
type of surge that is typically not destructive. Do we assume it
protects from ALL types of surges? Of course not. And yet that is
what many do when claiming a cheap UPS provides 'surge protection'.
They forget to mention the destructive type of surge it does not
protect from.
Again look at its numerical spec sheet. Where are numbers that
define protection for each type of surge? Numbers do not exist.
H-G, N-G that cover all surge modes. w_ has never provided specs from
anyone that had numbers for different surge modes. This is a red
hering.
Interconnected devices should connect to the same surge protector or
signal wires should run thorugh the surge protector.
Good information on surges and surge protection is available from the
IEEE at:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
And from the NIST at
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf
--
bud--
.
- References:
- Is Zone Alarm necessary with a DSL firewall?
- From: Pappion
- Re: Is Zone Alarm necessary with a DSL firewall?
- From: Sharon F
- Re: Is Zone Alarm necessary with a DSL firewall?
- From: Pappion
- Re: Is Zone Alarm necessary with a DSL firewall?
- From: Pappion
- Re: Is Zone Alarm necessary with a DSL firewall?
- From: Sharon F
- Re: Is Zone Alarm necessary with a DSL firewall?
- From: DanS
- Re: Is Zone Alarm necessary with a DSL firewall?
- From: w_tom
- Is Zone Alarm necessary with a DSL firewall?
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