Firewire hot plugging - safer using a switch?

[Richard901]

I have read several post on the dangers of hot plugging firewire audio interfaces and drives.

I have an M-Audio Ozonic keyboard. I am using this bus-powered using a firewire cable connected to an iMac.

The keyboard has an on/off switch. Is it OK to switch the keyboard off and then plug/unplug the firewire cable without switching the computer off?

Are the hot plug problems caused when the ‘live’ cable is just pulled out/pushed in leading to slight sparking, shorts, etc? Also, can similar problems occur when the firewire plug touches the socket, but is reversed?

I realise that the computer socket would still be live even if the keyboard is switched off, but would it help reduce problems.

I am in the process of modifying Pro Tools files so that they can be transferred from a G5 Mac to an Intel Mac, so switching the computers on and off to connect the keyboard is time consuming.


Thanks for your help.


Richard

[M.Brane]

It's perfectly fine to turn the power off on the device before swapping connections, but I use a powered hub as a buffer to protect the ports on the Mac from damage just in case.

Reversing a FW plug would be very bad becuse you would be introducing power onto the data lines. It would also mean that you're not paying much attention when pluging things in, and forcing them in the wrong way. These are delicate things not 1/4" phone plugs!

[Richard901]

Thanks for the quick reply – especially the idea about the powered hub.

Forcing in a reversed plug – I haven’t done that, but I find it easy to forget which way round the plug should go when I’m peering around the computer or keyboard. I sometimes TOUCH the plug against the socket before I realise that it is the wrong way. I was wondering whether some power could spark across (power onto the data lines?) even though it’s not pushed in.

The sensible thing would be for me to look at the socket and plug BEFORE touching them together, but I wonder whether this is a common mistake people make - especially with limited space/dim lighting, etc. Could this account for some of the firewire problems. Some type of colour or shape/feel identification would help.

Thanks again.

Richard

[M.Brane]

I bet some people manage to cram 'em in the wrong way. You'd have to force 'em in pretty far though to make the wrong connections, but I don't doubt that's been done. There is a guy I work with who's first response to anything that doesn't want to fit is to apply more force. Needless to say he often breaks things. Then he wonders why nobody trusts him around equipment.

It would be nice if the connectors were more robust, but I don't see that happening anytime soon. Price points, and all that.

Another thing I try to do if I can is touch something grounded just before plugging to guard against ESD.

I mounted my hub in the Zip bay of my G4 so I wouldn't have to deal with more cables laying around or go mucking about under the desk with a flashlight.

[Richard901]

Thanks again for your help.

Richard