Printing from camera USB socket?

October 28, 2006 4:55 AM

Why can't I print from my laptop using the digital camera socket on the front of my printer?

Got a HP 6940 printer which has a USB socket at the back - connected to my desktop - but I want to be able to use the USB socket at the front (which is for attaching a card reader or camera) to print from my laptop and so avoid all the plugging and unplugging. If I plug a camera in, I can print selected pics, so the socket works.

I have a USB cable with two male ends, but when I link up, the laptop does not recognise the printer as present and vice-versa. The laptop has the printer software loaded.

I thought this would be an easy way to solve my problem, but it seems not to work. Impossible, or am I doing something wrong?

posted by A189Nut to computers & internet (9 comments total)

That USB port on the front is most likely specifically for a card reader/camera. My Canon won't let me use the one on the front to print from my laptop either.
posted by Sar at 5:45 AM on October 28, 2006

Oh, but apparently you can use the front port on the hp6540 to print from a laptop, but only from a pict-bridge enabled camera on the hp6940. That sucks.
posted by Sar at 6:00 AM on October 28, 2006

It does suck. No way to fool the printer?
posted by A189Nut at 6:17 AM on October 28, 2006

It's a matter of host vs device or master vs slave. A laptop expects to own the USB bus and be the master; it knows how to control a printer, hard-drive, whatever that is behaving as a slave device.

Hard drives and cameras are slave devices using the mass storage protocol; i.e. a simple read/write interface that allows you to access linear media.

The digital camera port on the printer is a master port not a slave so the PC doesn't understand it. The printer has a little computer in it that understands the FAT filesystem and can read files from any hdd or camera you plug in that behaves like a mass storage device.

You can actually get special "USB On-The-Go" HDD enclosures now that can act as master or slave according to what you connect them to: when plugged into a PC, it's a mass-storage disc but when plugged into a card reader or camera, it switches to master mode, reads everything off the card and puts it on the disc.
posted by polyglot at 7:44 AM on October 28, 2006

polyglot's got the answer, but to piggyback... has anyone seen software that will cause a PC to fake being in slave mode? I looked a year ago and couldn't find anything, but it would be incredibly useful to me.
posted by Leon at 8:16 AM on October 28, 2006

The standard they're using is called PictBridge. Both the camera and the printer have to support it explicitly, and trying to use your laptop in the camera position doesn't work because your laptop doesn't know how to talk PictBridge.

Someone could write a client for the PC, but it doesn't appear anyone has, because most people just use the other USB port.
posted by smackfu at 10:04 AM on October 28, 2006

Yeah, you're not going to be able to hook up your laptop to the front of your printer.

Even more convenient: buy a cheap USB printserver, and hook it up to your router. You can now print wirelessly. Or second, why don't you share the printer on your PC and just print through it?
posted by mphuie at 11:49 AM on October 28, 2006

How would I do that (share the printer?) via the PC?
posted by A189Nut at 4:09 PM on October 28, 2006

Assuming you're in some variant of windows, you need to go to the network settings and enable Printer Sharing as one of the options. Once that's on, go to the Printers folder (under Control Panel I think), right click on your printer and one of the options is "Sharing...". Go in there, give it a name and it will be shared to all and sundry. I hope you've got a firewall on your internet connection or at least (if ADSL) a modem that does NAT.

Then from your other machine (laptop?), create a printer and tell it that it's a shared printer on your primary machine; you'll be able to browse to it. They'll need to be networked together for this to work.

(apologies for any missing steps here, I haven't used windows in anger for about 4 years and Windows 2000).
posted by polyglot at 6:11 PM on October 28, 2006