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Old 09-18-2012, 06:06 PM
Paul Hartman
 
Default UPS and serial or USB connections

On Tue, Sep 18, 2012 at 12:03 PM, Michael Mol <mikemol@gmail.com> wrote:
> On Tue, Sep 18, 2012 at 1:02 PM, Michael Mol <mikemol@gmail.com> wrote:
>> On Tue, Sep 18, 2012 at 12:17 PM, Paul Hartman
>> <paul.hartman+gentoo@gmail.com> wrote:
>>> On Tue, Sep 18, 2012 at 4:09 AM, Neil Bothwick <neil@digimed.co.uk> wrote:
>>>> Yes, I have blown a UART chip by hotplugging a serial cable, because I'd
>>>> got away with it before.
>>>
>>> The strangest thing I fried via hotplug was an Ethernet card via cat5
>>> cable insertion! It made a little electrical "pop" sound and that was
>>> the end of that.
>>>
>>> Actually, I nearly fried myself once when hotplugging coaxial cable TV
>>> wire into my television while everything was powered on. The shock
>>> launched me -- caused me to launch myself, probably -- up into the air
>>> and against a door, fully upright, from a seated position on the
>>> floor. In case anyone is concerned: the TV was unharmed.
>>
>> These weren't at the same locale, were they? That sounds like really
>> electrical ground.
>
> *like a really bad electrical ground. (htf?)

The ethernet incident happened at work, which should be grounded,
however it was in a cubicle... a cubicle that would give you the
tingles if you touched its metallic edges.

The TV was at my parents' house in the 1980's, an old home that
certainly does not have grounded electrical outlets. Plus I was
probably scooting around tall carpet in socks or something prior to
it.
 
Old 09-18-2012, 06:22 PM
Michael Mol
 
Default UPS and serial or USB connections

On Tue, Sep 18, 2012 at 2:06 PM, Paul Hartman
<paul.hartman+gentoo@gmail.com> wrote:
> On Tue, Sep 18, 2012 at 12:03 PM, Michael Mol <mikemol@gmail.com> wrote:
>> On Tue, Sep 18, 2012 at 1:02 PM, Michael Mol <mikemol@gmail.com> wrote:
>>> On Tue, Sep 18, 2012 at 12:17 PM, Paul Hartman
>>> <paul.hartman+gentoo@gmail.com> wrote:
>>>> On Tue, Sep 18, 2012 at 4:09 AM, Neil Bothwick <neil@digimed.co.uk> wrote:
>>>>> Yes, I have blown a UART chip by hotplugging a serial cable, because I'd
>>>>> got away with it before.
>>>>
>>>> The strangest thing I fried via hotplug was an Ethernet card via cat5
>>>> cable insertion! It made a little electrical "pop" sound and that was
>>>> the end of that.
>>>>
>>>> Actually, I nearly fried myself once when hotplugging coaxial cable TV
>>>> wire into my television while everything was powered on. The shock
>>>> launched me -- caused me to launch myself, probably -- up into the air
>>>> and against a door, fully upright, from a seated position on the
>>>> floor. In case anyone is concerned: the TV was unharmed.
>>>
>>> These weren't at the same locale, were they? That sounds like really
>>> electrical ground.
>>
>> *like a really bad electrical ground. (htf?)
>
> The ethernet incident happened at work, which should be grounded,
> however it was in a cubicle... a cubicle that would give you the
> tingles if you touched its metallic edges.
>
> The TV was at my parents' house in the 1980's, an old home that
> certainly does not have grounded electrical outlets. Plus I was
> probably scooting around tall carpet in socks or something prior to
> it.

I've nothing to say but that you've given me ample entertainment
today. (and your boss was lucky you hadn't fried the network
switch...)

--
:wq
 
Old 09-18-2012, 06:26 PM
"J. Roeleveld"
 
Default UPS and serial or USB connections

Neil Bothwick <neil@digimed.co.uk> wrote:
On Tue, 18 Sep 2012 09:51:49 +0200, J. Roeleveld wrote:

Plus, aren't you supposed to only unplug/plug a serial cable when it
is off? I'm not sure if they are sensitive to that but pretty sure
they were a long time ago.
Not sure about Serial, I always did even when switched on when using
external modems in the past and never did have a problem there.
You were lucky, it's like forgetting to look when you cross the road.
Getting away with it once doesn't mean it is safe.

Yes, I have blown a UART chip by hotplugging a serial cable, because I'd
got away with it before
.

Probably.

Don't have any serial devices anymore. Don't even bother plugging in serial port brackets either on mainboards that support it either.



All the devices I have with a serial port (switches/ups) can also be configured using a network interface



--

Sent from my Android phone with K-9 Mail. Please excuse my brevity.
 
Old 09-18-2012, 06:30 PM
"J. Roeleveld"
 
Default UPS and serial or USB connections

Paul Hartman <paul.hartman+gentoo@gmail.com> wrote:

>On Tue, Sep 18, 2012 at 4:09 AM, Neil Bothwick <neil@digimed.co.uk>
>wrote:
>> Yes, I have blown a UART chip by hotplugging a serial cable, because
>I'd
>> got away with it before.
>
>The strangest thing I fried via hotplug was an Ethernet card via cat5
>cable insertion! It made a little electrical "pop" sound and that was
>the end of that.
>
>Actually, I nearly fried myself once when hotplugging coaxial cable TV
>wire into my television while everything was powered on. The shock
>launched me -- caused me to launch myself, probably -- up into the air
>and against a door, fully upright, from a seated position on the
>floor. In case anyone is concerned: the TV was unharmed.

How was the door afterwards?

I think the biggest risk is from powerspikes due to bad earthing of the devices.
--
Sent from my Android phone with K-9 Mail. Please excuse my brevity.
 
Old 09-18-2012, 06:30 PM
Dale
 
Default UPS and serial or USB connections

Volker Armin Hemmann wrote:
> Am Dienstag, 18. September 2012, 04:50:30 schrieb Dale:
>
>> One would think that modern stuff would have some sort of protection.
>> Odd.
>>
> indeed. The modern stuff with protection is called 'usb'.
>
>

Well, I meant for the serial/parallel chips tho. Surely it can't be
hard to at least keep them from blowing their fuse.

Dale

:-) :-)

--
I am only responsible for what I said ... Not for what you understood or how you interpreted my words!
 
Old 09-18-2012, 06:52 PM
Michael Mol
 
Default UPS and serial or USB connections

On Tue, Sep 18, 2012 at 2:30 PM, Dale <rdalek1967@gmail.com> wrote:
> Volker Armin Hemmann wrote:
>> Am Dienstag, 18. September 2012, 04:50:30 schrieb Dale:
>>
>>> One would think that modern stuff would have some sort of protection.
>>> Odd.
>>>
>> indeed. The modern stuff with protection is called 'usb'.
>>
>>
>
> Well, I meant for the serial/parallel chips tho. Surely it can't be
> hard to at least keep them from blowing their fuse.

If it's TTL, no problem. If it's CMOS, it requires extra work (and
cost) in an environment where every penny off of a component is
important. Point is, RS-232 and IEEE-1284 weren't designed for
hotplug, and plug/unplug events are very, very rare. Manufacturers are
under no obligation to extend support beyond spec, and it doesn't make
sense for them to, given that USB is available where it's necessary.

USB, on the other hand, was explicitly designed to handle hotplug. It
even shows in comparison to the connectors it replaces; DB-25, DB-9
and Centronix connectors typiclaly have explicit mechanisms to retain
devices and prevent them from accidentally unplugging. DB-25 and DB-9
connectors didn't originally even come with thumbscrews; I've still
got some cables laying around that require the use of a small
screwdriver. No such manual step with USB, as it's an expected event.

--
:wq
 
Old 09-18-2012, 06:55 PM
Neil Bothwick
 
Default UPS and serial or USB connections

On Tue, 18 Sep 2012 13:30:52 -0500, Dale wrote:

> >> One would think that modern stuff would have some sort of protection.
> >> Odd.
> >>
> > indeed. The modern stuff with protection is called 'usb'.

> Well, I meant for the serial/parallel chips tho. Surely it can't be
> hard to at least keep them from blowing their fuse.

The problem is in the connectors, it's too easy to get a static discharge
when connecting them. USB has grounded shields over the connectors.


--
Neil Bothwick

I@love~my,;It's%made in Taiwa~##$ ` #@
 
Old 09-18-2012, 08:19 PM
Dale
 
Default UPS and serial or USB connections

Michael Mol wrote:
> On Tue, Sep 18, 2012 at 2:30 PM, Dale <rdalek1967@gmail.com> wrote:
>> Volker Armin Hemmann wrote:
>>> Am Dienstag, 18. September 2012, 04:50:30 schrieb Dale:
>>>
>>>> One would think that modern stuff would have some sort of protection.
>>>> Odd.
>>>>
>>> indeed. The modern stuff with protection is called 'usb'.
>>>
>>>
>> Well, I meant for the serial/parallel chips tho. Surely it can't be
>> hard to at least keep them from blowing their fuse.
> If it's TTL, no problem. If it's CMOS, it requires extra work (and
> cost) in an environment where every penny off of a component is
> important. Point is, RS-232 and IEEE-1284 weren't designed for
> hotplug, and plug/unplug events are very, very rare. Manufacturers are
> under no obligation to extend support beyond spec, and it doesn't make
> sense for them to, given that USB is available where it's necessary.
>
> USB, on the other hand, was explicitly designed to handle hotplug. It
> even shows in comparison to the connectors it replaces; DB-25, DB-9
> and Centronix connectors typiclaly have explicit mechanisms to retain
> devices and prevent them from accidentally unplugging. DB-25 and DB-9
> connectors didn't originally even come with thumbscrews; I've still
> got some cables laying around that require the use of a small
> screwdriver. No such manual step with USB, as it's an expected event.
>

I know it would take extra work but one would think that some company
would do it then everyone else will follow. I'm not saying the
communication part should work when you plug up something, just that it
shouldn't burn out a chip so that it never works again. It should at
least have some forgiveness to the occasional accident of unplugging a
cable.

Oh well, me thinking it isn't going to change it. ;-)

Dale

:-) :-)

--
I am only responsible for what I said ... Not for what you understood or how you interpreted my words!
 
Old 09-18-2012, 08:21 PM
Dale
 
Default UPS and serial or USB connections

Neil Bothwick wrote:
> On Tue, 18 Sep 2012 13:30:52 -0500, Dale wrote:
>
>>>> One would think that modern stuff would have some sort of protection.
>>>> Odd.
>>>>
>>> indeed. The modern stuff with protection is called 'usb'.
>> Well, I meant for the serial/parallel chips tho. Surely it can't be
>> hard to at least keep them from blowing their fuse.
> The problem is in the connectors, it's too easy to get a static discharge
> when connecting them. USB has grounded shields over the connectors.
>
>


Somewhat off topic, how about a monitor that uses the 15 pin connector?
I try not to do those when something is powered up but have done it a
couple times. Is that one safe to hotplug? I never thought about that
until this came up.

Dale

:-) :-)

--
I am only responsible for what I said ... Not for what you understood or how you interpreted my words!
 
Old 09-18-2012, 09:00 PM
Paul Hartman
 
Default UPS and serial or USB connections

On Tue, Sep 18, 2012 at 3:21 PM, Dale <rdalek1967@gmail.com> wrote:
> Neil Bothwick wrote:
>> On Tue, 18 Sep 2012 13:30:52 -0500, Dale wrote:
>>
>>>>> One would think that modern stuff would have some sort of protection.
>>>>> Odd.
>>>>>
>>>> indeed. The modern stuff with protection is called 'usb'.
>>> Well, I meant for the serial/parallel chips tho. Surely it can't be
>>> hard to at least keep them from blowing their fuse.
>> The problem is in the connectors, it's too easy to get a static discharge
>> when connecting them. USB has grounded shields over the connectors.
>>
>>
>
>
> Somewhat off topic, how about a monitor that uses the 15 pin connector?
> I try not to do those when something is powered up but have done it a
> couple times. Is that one safe to hotplug? I never thought about that
> until this came up.

VGA is not hot-pluggable by specification, but DVI and HDMI are hot-pluggable.
 

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