connecting 2 usb cables together

[olrob]

I have an external disk (HDD) usb connected to my dell pc with a standard usb cable. I connected two usb cables together via a 4 port usb hub without power and connected them between my pc and HDD. All works fine. I obtained some usb adapters which are similar to the hub, but much cheaper, with one B female (Bf) & one Af receptacle. When I substitute the adapter for the hub the pc says "no good" (paraphrased). I tried two adapters with the same result. Can't test the pin to pin continuity with my multimeter 'cause it's difficult to get the multimeter probes to touch the adapter pins.
What is different, electrically & pin wise, between the hub and the adapter? Both connect via Af & Bf receptacles to usb cables and all cables check out ok. Every description of usb pinouts say the same thing, pins 1 & 4 carry power and ground and pins 2 & 3 carry data.
Thanks

[glc]

I may be missing the concept, but why don't you just get a longer single USB cable?

[mojo]

The hub actively repeats the signal, while your adapters do not. How long do you need the run to be? They also make usb extension cables that you might want to look at.

[olrob]

My problem originally was not cable length. I have 2 pcs and I wanted to switch the HDD from one to the other pc. It allows me a fairly fast file sharing capability. Since I had a 4 port usb hub I tried that first and it worked. It also allows me to use two 3' usb cables to reach 6'. I could also use two cables each connected to a pc and one cable connecting the HDD to the hub and manually switch the HDD between pcs at the hub. I only use the Bf port and one of the four Af ports of the hub.

pc|Af||Am......cable......Bm|| Af
or ||Bf=hub=Af||Am......cable.....Bm||Bf| HDD |
pc|Af||Am......cable......Bm|| Af


I thought the adapter would do the same since it had one Bf port and one Af port so I bought 3 adapters. This would have allowed me to reach 6' with two cables and 1 adapter or 18' using three cables and two adapters. In addition, I could use two cables each connected to a pc as indicated above and manually switch the HDD between pcs at the adapter.

||Bf=adapter=Af||Am......cable.....Bm||Bf| HDD |


Alas, it no work!!

Thanks RobRoy

[glc]

To share a USB device between 2 computers like that, you have to use an active device of some sort. Your hub apparently has the same characteristics as a sharing switch.

Why don't you just network the 2 computers?

[olrob]

Thanks for responding. I have had limited success with networking. They are both cable connected into a Linksys 4 port router and each readily has internet access. The router is also wireless-B so I can WI-FI to other pcs that have usb wireless adapters and a NIC.

I have set up printer sharing so the pc without a printer can print on the other pc's printer. But file sharing has not worked for a number of reasons. I also do not get along with the darn Network Wizard!!

I set up the sharing of the external 80 GB HDD because I had two other Dell pcs I was fixing for friends. I only have one monitor so I use a Belkin 2-port KVM switch and can easily switch the monitor, wireless keyboard & mouse and sound amp & speakers to the pc I want to use. I was also able to move files and folders from one pc to the other at high speed via the switchable HDD with the usb hub.

Do you have any references that clearly explain how to set up file sharing between two pcs?

[glc]

What exact version of Windows do you have on the 2 PC's? If you have printer sharing working, getting file sharing going should be simple. No need to use the wizard at this point, we can do it manually.

[olrob]

Win XP SP2 on both.

[glc]

Home, Pro, or MCE?

[olrob]

Win XP home SP2.

I have overcome (not solved) the problem. I talked to a tech for a firm that sells adapters and hubs. He assured me that the adapter only has straight through connections from pin to pin. He also said usb connections can be fickle. Two cables with an adapter between should work between a device and a pc as long as the total length is no more than about 5 meters. But the adapter can present an interference/impedance/mismatch (connector to connector twice) and if not shielded can pick up some signal interference.
My initial try was 2 cables (A & B) and adapter between an external hard disk (EHDD) and a pc's usb port which only worked when I used a hub. Next, I tried 2 different cables (C & D) and adapter between my printer and pc and, to my surprise, it worked. I surmised that both cables and adapter were matched somehow. I then took one of these cables (C) and replaced the original adapter to pc cable (A) and (again to my surprise) it worked. Cable A was compatible with the hub (which also reconstructs the signal as explained by MOJO) but not the adapter.
When I used cable A, adapter and cable D with my printer to pc link it also worked.
I now have a link to the EHDD and another link to the printer and I can switch them (manually disconnect one cable and connect another) to either pc. I also demonstrated that "hot-switching" peripherals can work fine.

Thanks for all your help. I hope this explanation can also help any newbe that has usb cable problems.