Question about "hot" disconnects.

[Brax]

I have my I-PAC hooked up to my computer through the USB cable. Inbetween the I-PAC and the controls I have a DB25 connector so I can remove the control panel.

The I-PAC would remain connected to the computer. Can I remove the db-25 connector "hot" without damaging anything?

[ErikRuud]

Yes you can.  That is one of the great things about the IPac.

[Brax]

Is this true with both the USB I-PAC and the ps/2 I-PAC?

I would think so but confirmation would be nice.

[Carsten Carlos]

There isn't any difference anyway between the USB & the PS2/I-Pac. As far as I know, there is only the USB-cable additonal packaged, and you can decide with a jumper on the PCB whether you want to use is at as USB or PS2.

And of course, hot unplugging works perfectly!

[Brax]

Hot unplugging a USB is a no-brainer. Thats not what I was asking.

I'm unplugging AFTER the I-PAC (inbetween the I-PAC and the controls) I will be still be connected to a running computer. (whether I'm using USB or PS/2) I just wanted to make sure I wouldn't damage anything.

From the previous replys it appears I won't. It sounds like as long as the I-PAC remains plugged into the computer it isolates my DB-25 connector.

[Carsten Carlos]

Hot unplugging a USB is a no-brainer. Thats not what I was asking.

And that wasn't what I was talking about. But you asked for the I-Pacs as if they were different types which they are actually not.
Anyway, why would anyone hotplug the I-Pac itself?! Would be good for Andy though, if you would buy extra-Ipacs for every controlpanel you make.  

[kspiff]

I have another question in this vein.. I'm going to be using several DB-15 connectors (P1-P4) and running all the ground/common wires through the P1 connector.. will I need to be careful that I don't unplug P1 with P2-4 still connected?

k-spiff

[cdbrown]

kspiff,

By removing P1 you remove the ground which breaks the signal loop making P2-4 not work.  Just plug it back in and everything will be fine.

That's the way I see it, but I could be wrong .

Cheers
-cdbrown

[Carsten Carlos]

That's the way I see it

Agree on this. Are you building a modular controlpanel or why do yo wanna use 4 plugs?

Maybe think about the SCSI-1-cables with centronicsplug. I switched over to use them as my former plug was way to sticky and hard to pull, and you get 50 pins with easy handling!  

[Brax]

And that wasn't what I was talking about. But you asked for the I-Pacs as if they were different types which they are actually not.

No. I actually wasn't. I'm quite aware that they are the same device, but they are different connections aren't they? You can hot unplug USB and you CAN'T hot unplug a PS/2 device. I didn't think it was too off the wall to inquire about hot unplugging after the I-PAC when using PS/2 mode. I didn't think it was particularily difficult to understand, but apparently it was.

Yes, it's the same I-PAC but i wanted to know if the type of CONNECTION affected anything.

Whatever. My question was answered before you even started any of this crap anyways.

[eightbit]

There is some old wives tale about plugging in a PS/2 keyboard (small plug) while it was turned on because there is actually power to it. I talked to guys in engineering over at Compaq a while back about hot plugging a keyboard into a server and they said it wouldn't  be a problem.

Your situation is even less of a problem since your not unplugging the IPAC your only unplugging the switches. As far as the computer is concerned the keyboard is still there even if there isn't anything hooked to the IPAC.

So I'd say go ahead and do it, I'm planning to. I'm just trying to decide what type of connector to use.  

[Brax]

I prefer having one connector personally.

That would leave a db-25 or a scsi cable. I used the db-25 because i could buy the components easily and it made for nice neat solders, since its a kit.

I didnt't have easy access to a scsi cable and I thought all the splices would look a little messier. I think the scsi cable attaches and detaches easier though, but fo ras often as I remove my panel that wasn't an issue for me.

Both solutions work just fine, its just personal preference.

[Lilwolf]

Yes you can remove a cp without any harm for all of the major keyboard encoders.

why?

when you unplug them all... is the same as unpressing all the buttons.  When you press a button, it makes a connection between the ground and the button.  Well, when no buttons are pressed, it looks 100% the same as having the cp unplugged.

Plugging in extra lengths of wire that are connected to a non-connected line is well the same.

[wee beastie]

So, you guys are suggesting to use a printer/serial or whatever comp cable (assuming it has a male and female end) to allow for swappable control panels.  I had an extra printer cable laying around (DB-25), so I cut it open to take a look.  The wires in the printer cable, do not seem to be the same guage as the wiring underneath my control panel.  Will this still work?

[eightbit]

I've asked that same question a couple times and there are people doing it. I was also concerned about the size of the wire but apparently it works. What you need is a printer extension cable. that gives you the male and female ends and its wired straight through. Meaning every pin is the same pin on the other end. I've found that different brands of extension cables use different colors for different pins so if you use different cables you can't wire it based on color.

I got lucky and found 10 extension cables being thrown out yesterday at work that are all identical so I started wiring my IPAC last night with one of them. I tested a couple buttons and it appears to work.

[Carsten Carlos]

Whatever. My question was answered before you even started any of this crap anyways.

Say, got any problems? Or why so aggressive? No need to reply, isn't worth to deal with. I just remembered this as a friendly place.

[wee beastie]

Thanks for the help!  I figured that it would work, but i just wanted to confirm.

Carsten, I think he was making light of it.  Probably didn't mean to offend.

[wee beastie]

Ok, so I have another question about the printer cable.  Upon further inspection, the cable has 18 PAIRS of wire in it (36 total wires).  Considering the cable only has 25 pins, I assume that one pair of wires corresponds to a pin?  Is this correct?  (if this is, that means that there are "dead" pins in the cable)?

[wee beastie]

no one knows the answer?

[Tiger-Heli]

no one knows the answer?

I don't, although I wouldn't be surprised at all that a printer cable does not use ALL 25 pins.

Basically, you need to get a cheap multi-meter ($5-10) or a continuity tester and figure out which wire goes to which pin and label them.

[cdbrown]

wee beastie,

Most printer cables don't use all pins and such don't have all the wires.  I went and bought extension cables which do use all the pins and contain 25 wires plus an unshielded ground wire.  Try to get db25 extension cables and not printer extensions.  The DB25 extension cables are pretty much generic and are made so that it will work with anything that has a db25 connector.  The printer cables are made specifically for printers ( funnily enough) and won't work for other equipment.  This has been bought up in a previous thread.

The printer cable with 18 pairs of wires might be because it's a bidirectional cable.  I have seen these at the computer store, the guy there said they are used with printers that send info back the the printer but didn't really know any more than that.  They were more expensive so I just got the plain 2nd hand extension cables.  I have cut them all in half and it looks like all the wires are there.

Hope this helps
Cheers
-cdbrown

[eightbit]

I second what he said. I've been trying to post that for 2 days and keep having trouble with the message board.

The only problem with using printer extension cables that I've found is different brands use different colors for the same pin. Meaning you can't wire based on color if you have multiple brands of cables. Not a big problem for me since work was throwing out a whole box of identical cables.

[Psyklops]

FYI
   
     I crimped my wires running from my controls into a 25-pin female connector.  Then I crimped the wires running from my IPAC into another 25-pin female connector.  I then went out and bought a Belkin 10' 25-pin Male-to-Male Switchbox cable to run between the two.  This is working perfectly and if a pin ever gets bent on the cable, it's a simple matter to replace the cable and plug it in.  Instead of having to buy a new cable, cut it up, strip the cable ends and then reattach it to the appropriate terminals.

[wee beastie]

Thanks guys

[eightbit]

Thats a pretty cool idea. I was worried about the distance on such a small wire but if your using a 10' cable then it must work. I also didn't want to have the extra cable coiled up in the cabinet but I suppose if you wanted to you could easily find a shorter cable.

[Carsten Carlos]

I still must hold my torch for SCSI-1-centronics-cables. They plug easy, have always 50 wires in it, so you have also enough connectors for your Optipac reserved! When you buy them on the right places, they are even cheap!

Though noone needs to do it such complicate looking like I did  



(OptiPac currently not connected)

[Psyklops]

Thats a pretty cool idea. I was worried about the distance on such a small wire but if your using a 10' cable then it must work. I also didn't want to have the extra cable coiled up in the cabinet but I suppose if you wanted to you could easily find a shorter cable.

I don't have a full cabinet built yet, I just got my controls 2 weeks ago and this is what I have hooked up for two 1-player joysticks.  I have a board with the IPAC mounted to it and 2 of the 25pin female connectors.  One is wired to P1 controls the other to P2 Controls.  Then I have 2 1-player joysticks each with a 25-pin female connector in the back.  Then I have a 10' 25-pin male to male swtich box cable running between each to the IPAC "hub".  

I found this a nice approach as opposed to building a massive 2-player stick for placing in your lap when sitting at the computer desk.  But the cabling is pretty much the approach I'm going to take when I wire a cabinet up later this winter.