JP1 Remotes

[bgc99]

Hi,
I'm waiting on a JP1 cable that I ordered and thought I'd ask this. Does it matter if the cable is connected to or disconnected from the remote while the computer is running or does that require a shutdown?

Thanks,
BGC

[johnsfine]

It doesn't require any such precautions. Printer ports are designed to be connected and disconnected with power on anyway and the JP1 cable has resistors limiting the current flow in case it is connected wrong.

[hhyatt]

I had always heard NOT to change LPT connections with power on. I have an AB switch that I have printer and JP1 interface connected to. Based on past instructions, I always power down before changing from one to the other. I know that USB can be hot-switched, but I thought that LPT could not. Furthermore, the source that I got this from x years in the past said that hot-switching LPT could damage the computer.

What have other heard, or better still can you point me to a definitive resource that says that hot-switching LPT (parallel/printer) ports is allowed?
_________________
HGH

[Filebug]

Isn't flipping the switch on your A/B box the same as manually unplugging one parallel device and plugging in another?

I agree I have always heard never hotswap anything from your LPT port and have heard the same with the PS2 ports. Of course I've never powered down and have never had or heard of anyone having a problem from not powering down.
_________________
-Tom

[zaphod7501]

As an electronic tech I think your biggest worry would be static electric discharge damaging the PC (and this would be the same possibility even if the PC was turned off). Mechanical A/B switches (as opposed to electronic) generate a lot of electrical NOISE , personally I would be more likely to power down the PC with one of them than than if I was going to swap cables. There is basically nothing in the JP1 interface (unlike a printer) so I think the most important thing would be to make sure the printer was powered down before disconnecting it.
_________________
Just call me Zaphod (or Steve) --- I never should have started using numbers in a screen name but I just can't stop now.

[classicsat]

Doesn't matter, I connect/disconnect JP1 and aother bit-banged LPT port programmers with no ill effect to the PC or device.

[hhyatt]

So it seems that there is little, if any, concern for hot-swapping/hot-switching LPT ports. What was the concern in the past -- I have seen this as a standard of practice in published literature.

The comment about static surges would seem to have the best foundation -- is this because the LPT to standard printer is a relatively high current application while JP1 is elecronically isolated and uses virturally no current ??

This is no big issue, I just want to know what the basis of the "old rules" was. There was so much to learn that a person didn't have time to understand why -- in most cases we took a lot of things on faith.
_________________
HGH

[Mark Pierson]