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- Shared DOK?
May 8, 2006, 2:09 pm
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Re: Shared DOK?
What's a DOK?
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Re: Shared DOK?
(I had to look it up...)
One way to share a USB device, is with one of these Peripheral
Sharing Switches. But if you read the manual, you still have
to "Eject" the device on one computer (which makes sure the
device is "closed" before disconnection), before pushing the
button and connecting the USB flash device to the next computer.
All this saves, is the wear and tear on the connector of the USB
flash device. It doesn't make the task more convenient. Only
one computer talks to the shared USB device at a time, then
you "Eject", push the button on the switching device, and
use the USB flash on the next computer.
In the old days, software like Laplink allowed connecting two
computers via a serial connection. Now, they probably did not
use a TCP/IP stack, and probably had restricted functionality
back in those days.
I think there is a tendency of the product now, to using
a TCP/IP stack. It is unclear to me, whether their file
transfer option, is using a Windows share, or is using a
proprietary method. If it was proprietary, then no TCP/IP
packets could "leak through".
One product mentioned in the Laplink documentation, is
this USB to USB cable.
There are two versions of the SmartLink, and the surprise is
that the USB 2.0 version is discontinued, while the USB 1.1
(slower) version is still for sale.
The basic mechanism inside that cable, is a single chip. The
chip has two USB ports. It has buffers going in each direction.
When you connect the cable, the driver provided runs a networking
stack (unfortunate in your case). Apparently, Laplink can also
use the cable, but the most likely scenario, is Laplink sits on
top of the network stack, rather than dealing directly with
the hardware primitives. That makes it hard to say
whether a SmartLink meets your requirements or not.
And the Laplink documentation also rules out using two
USB to RS-232 devices, to go from one computer to the other.
You would think, if flow control was properly supported on
the RS-232 connector, that it would work.
Your problem may have been easier to solve 10 years ago,
when the program didn't have quite as much intelligence.
Virtually every other solution I can think of, uses a
OK. Here is an idea :-) Should be good and slow.
Maybe some Kermit is in order.
A couple of these wired back to back, with no RS-232
level shifters, and you'd have a dandy Kermit USB
to USB adapter. The reason for using these, is an
RS-232 driver is loaded, and no pesky TCP/IP.
Ones like this would be quite a bit slower, as the RS-232
part of the adapter tends to limit the speed. I think the claim
for these, is somewhere around 460Kbits/sec. Wire two of
these back to back, with a RS-232 null modem adapter. Then
run Kermit on top of it. The 60KB/sec transfer rate would
be similar to the speed of a floppy disk drive.
Re: Shared DOK?
Thanks but any ip based stuff wont fit here.
Our security policy says: no wire - no hackers.
Therefor, we transfer data between isolated systems only on disk on
I guess that when we have enough money we'll buy some shared storage
I'll think of crafting somethin using com ports..