Is the keyboard hot pluggable?

[Franc Zabkar]

While not a good idea, I've done it on about every system I've ever owned.
The current one falls out every few weeks or so, at which time I plug it
back in and go about my business.

The only thing that is noticeably different is that the typematic rate
changes, at least until the next boot.

I wouldn't recommend it, though.

Jon

I have two Win9x systems connected to a passive KVM box. Whenever I
switch between them, the typematic settings are lost.

To work around this, I have a desktop shortcut which I access with
Ctrl_Alt_K and which executes the following command line:

C:\WINDOWS\COMMAND\MODE.COM con rate=32 delay=1

I don't know if a similar technique will work for Win2K and above.

- Franc Zabkar

 

[Franc Zabkar]

Can the keyboard be safely unplugged, and plugged back in
with the power turned on?

I have a passive KVM box that connects two computers to an old
AT-style keyboard. AFAICS, switching between PCs is akin to
hotplugging the keyboard. I've done this hundreds of times without
incident. I would think that a properly designed KVM box should make
the power contacts before making the signal contacts, as is the case
with USB, but my box appears to have only a simple multipole rotary
switch.

- Franc Zabkar

 

[Andrew Smallshaw]

I have a passive KVM box that connects two computers to an old
AT-style keyboard. AFAICS, switching between PCs is akin to
hotplugging the keyboard. I've done this hundreds of times without
incident. I would think that a properly designed KVM box should make
the power contacts before making the signal contacts, as is the case
with USB, but my box appears to have only a simple multipole rotary
switch.

ISTR AT style keyboards should be hot pluggable, in practice even
if not by design (similar to serial and parallel ports). It is
PS/2 ports that are potentially troublesome. Even then, many
mobo/keyboard combinations are perfectly happy with hot-plugging,
it is just there is no way of knowing if yours happens to be one
of them before trying it, by which time it may be too late.

Of course, I've no idea how this relates to the fact the two types
are electrically identical and you can easily adapt AT to PS/2 and
vice versa... the connections on an AT keyboard are standard 5-pin
DIN AFAIK, there's no differentiation in contact length. Maybe it
is simply standard practice that AT keyboard sockets have the
necessary protection in place.

 

[Jon Danniken]

"Franc Zabkar" wrote ,

"Jon Danniken" put finger to keyboard and composed:

I have two Win9x systems connected to a passive KVM box. Whenever I
switch between them, the typematic settings are lost.

To work around this, I have a desktop shortcut which I access with
Ctrl_Alt_K and which executes the following command line:

C:\WINDOWS\COMMAND\MODE.COM con rate=32 delay=1

I don't know if a similar technique will work for Win2K and above.

Thanks, Franc, I'll give that a whirl the next time my cord becomes yanked.

Jon

 

[Peter Olcott]

"Franc Zabkar" wrote ,

Thanks, Franc, I'll give that a whirl the next time my
cord becomes yanked.

Jon

The fact that the keyboard was not designed to be hot
pluggable was apparently the root cause of my problem. My
keyboard was destroyed. The PS2 port worked OK with another
keyboard, but, the optimal solution that I chose was to
switch to a hot pluggable USB keyboard. I have been using a
USB mouse for years.

 

[Lord Turkey Cough]

Can the keyboard be safely unplugged, and plugged back in with the power
turned on?

I do it all the time on both my computers with PS2 ports.
No problems whatsoever.
I would not hesitate to do it on a brand new computer.

 

[Lord Turkey Cough]

Can the keyboard be safely unplugged, and plugged back in with the power
turned on?

Yes. Well PS2 is for sure, I have done it on both my computers
with no problem.
Hard to see how any hard couldbe done

 

[Peter Olcott]

I do it all the time on both my computers with PS2 ports.
No problems whatsoever.
I would not hesitate to do it on a brand new computer.

It ruined my keyboard to I switched to a USB keyboard.

 

[Lord Turkey Cough]

It ruined my keyboard to I switched to a USB keyboard.

??? how can you ruin a keybooard?

All you are doing is plugging it it, ie giving it power, which is
the same as you so when ou power your computer up.

I fail to see how any device can not be hot pluggable, to be honest.

 

[Calab]

??? how can you ruin a keybooard?

More likely he meant it ruined the keyboard port on the PC.

All you are doing is plugging it it, ie giving it power, which is
the same as you so when ou power your computer up.

I fail to see how any device can not be hot pluggable, to be honest.

Plug is half way in... the 5v and data lines have made contact, but not
ground. All power is shunted through the data leads - *POP*

 

[kony]

??? how can you ruin a keybooard?

All you are doing is plugging it it, ie giving it power, which is
the same as you so when ou power your computer up.

I fail to see how any device can not be hot pluggable, to be honest.

Do you feel the same way about your video card, can it be
put in and taken out while the system is running?

 

[larry moe 'n curly]

I fail to see how any device can not be hot pluggable, to be honest.

Then why are so many companies making special hot-swap chips just to
protect devices against hot plugging? Example:

www.maxim-ic.com/appnotes.cfm/an_pk/2736

 

[Paul]

??? how can you ruin a keybooard?

All you are doing is plugging it it, ie giving it power, which is
the same as you so when ou power your computer up.

I fail to see how any device can not be hot pluggable, to be honest.

http://en.wikipedia.org/wiki/Hot_swap

Protocols that now support hot swapping include PC card, USB, FireWire,
Fibre Channel, SATA, SCSI and SAS.

Protocols that do not support hot swapping include PATA and PS/2

If you look closely at the connector design on hot swap components, some
pins may be longer than others. In the following example, the six ground
pins are longer than the others, and the ground pins make contact first.
Doing such things, is to prevent reverse potentials from appearing on data
pins. PS/2 has the pins all the same length, and any one could make contact
before the others.

http://www.shopaddonics.com/mmSHOPADDONICS/Images/AASA4PPC.gif

Even Firewire, although it is listed in the hot swap list above,
is not considered entirely safe by its user base. Experienced
users connect Firewire cabling, before powering up their system.

HTH,
Paul

 

[Lord Turkey Cough]

More likely he meant it ruined the keyboard port on the PC.


Plug is half way in... the 5v and data lines have made contact, but not
ground. All power is shunted through the data leads - *POP*

Even if that were true you could simply make the data connection shorter.

 

[Lord Turkey Cough]

http://en.wikipedia.org/wiki/Hot_swap

Protocols that now support hot swapping include PC card, USB, FireWire,
Fibre Channel, SATA, SCSI and SAS.

Protocols that do not support hot swapping include PATA and PS/2

If you look closely at the connector design on hot swap components, some
pins may be longer than others. In the following example, the six ground
pins are longer than the others, and the ground pins make contact first.
Doing such things, is to prevent reverse potentials from appearing on data
pins. PS/2 has the pins all the same length, and any one could make
contact
before the others.

Just made a comment about pin lengths before I read this.
It's prettty obvious really.
Anyhow I don't give a second thought to unplugging or swappinig keyboards
whilst powered up. I used to do it regularly.
5 volts is negligible, they have to cope with that anyway.

My USB2 digital TV stick won't work unless it is plugged in from
power up though, but I expect that is down to crap software.

 

[kony]

Even if that were true you could simply make the data connection shorter.

What do you mean "could"? You are suggesting the entire
world lop off the connectors and make some new proprietary
connector and solder it on?

However, in all fairness the ground should make contact
before anything else because the outer metal rim is grounded
as is the frame of the connector shell. It still doesn't
eliminate the chance of transient surges, basically what it
boils down to is that in this industry parts are designed as
cheaply as possible and that means that if something doesn't
"NEED" to be hot pluggable, if there's a way to save a penny
by not supporting it, you can bet someone didn't.

 

[kony]

Just made a comment about pin lengths before I read this.
It's prettty obvious really.
Anyhow I don't give a second thought to unplugging or swappinig keyboards
whilst powered up. I used to do it regularly.
5 volts is negligible, they have to cope with that anyway.

My USB2 digital TV stick won't work unless it is plugged in from
power up though, but I expect that is down to crap software.

This is a situation a bit like ESD damage. I mean you can
do it 100 times and have no problem, but that doesn't change
the fact that the 101st time you might have a problem
because it wasn't designed to accomodate this.

 

[Franc Zabkar]

Just made a comment about pin lengths before I read this.
It's prettty obvious really.
Anyhow I don't give a second thought to unplugging or swappinig keyboards
whilst powered up. I used to do it regularly.
5 volts is negligible, they have to cope with that anyway.

http://en.wikipedia.org/wiki/Latchup

"A latchup is the inadvertent creation of a low-impedance path between
the power supply rails of an electronic component, triggering a
parasitic structure, which then acts as a short circuit, disrupting
proper functioning of the part and possibly even leading to its
destruction due to overcurrent."

"It is possible to design chips that are latchup-resistant, where a
layer of insulating oxide (called a trench) surrounds both the NMOS
and the PMOS transistors. This breaks the parasitic SCR structure
between these transistors. Such parts are important in the cases where
the proper sequencing of power and signals cannot be guaranteed (e.g.,
in hot swap devices)."

- Franc Zabkar