I am running a Ubuntu 14.04 LTS and some unusual serial hardware, which is converted to USB.

I bought a 3.0 USB hub made by Orico. It has 4 ports, and it is powered by the USB port it plugs into. It is made out of metal, and is very nice looking.

I was baffled for a while... until I removed the USB hub and connected all devices directly to the PC... then everything started to work like a charm. My questions are along the line of:

1. Is the USB Hub I am using poorly built or will other hubs exhibit the same behavior?
2. how do I figure out what happens when I use the USB hub? I mean, how can I figure out what went wrong? can I do a speed test to figure out if the speed drops, or if there is a voltage drop, or perhaps collect some error code from the USB controller registers?
3. I need the hub to carry all the serial data that gets converted to USB messages to the PC without a bottleneck; and when we consider that the serial speeds of my RS232 and RS422 devices are so slow (compared to USB... not my troubleshooting speeds...) I would think that any hub will do the trick. Having discovered this issue, I am curious why a hub with speeds much faster than the devices connected to it is acting as a bottle neck.

Does this mean that I cannot use a USB hub?!?

I am running a Ubuntu 14.04 LTS and some unusual serial hardware, which uses serial to USB converters.

I am unable to plug several slow devices (RS232 to USB 2.0 converter, and RS422 to USB 2.0 converter, and another USB 2.0 device) into a 3.0 hub without having my application crash due to lack of incoming messages. However if all the devices are plugged directly into the PC everything works. Could you please explain why this is happening? Please read on for details...

I bought a 3.0 USB hub made by Orico. It has 4 ports, and it is powered by the USB port it plugs into.

I was baffled for a while... until I removed the USB hub and connected all devices directly to the PC... then everything started to work like a charm.

Could you please expalain why this is happening? As well, could you please suggest some tools or a proceedure to help me pinpoint exactly what is going wrong with the USB network?

I need the hub to carry all the serial data that gets converted to USB messages to the PC without a bottleneck; and when we consider that the serial speeds of my RS232 and RS422 devices are so slow (compared to USB... not my troubleshooting speeds...) I would think that any hub will do the trick. Having discovered this issue, I am curious why a hub with speeds much faster than the devices connected to it is acting as a bottle neck.

Does this mean that a USB hub cannot pass the data passed to it by 2 serial devices and a single USB device at the rate at which the messages are arriving? This sounds really off.

If I can provide more info, please let me know. Thanks in advance.

1. Is the USB Hub I am using poorly built or will other hubs exhibit the same behavior?
2. how do I figure out what happens when I use the USB hub? I mean, how can I figure out what went wrong? can I do a speed test to figure out if the speed drops, or if there is a voltage drop, or perhaps collect some error code from the USB controller registers?
3. I need the hub to carry all the serial data that gets converted to USB messages to the PC without a bottleneck; and when we consider that the serial speeds of my RS232 and RS422 devices are so slow (compared to USB... not my troubleshooting speeds...) I would think that any hub will do the trick. Having learned my lesson, is this hub simply crap or will other hubs behave in a similar manner.

1. Is the USB Hub I am using poorly built or will other hubs exhibit the same behavior?
2. how do I figure out what happens when I use the USB hub? I mean, how can I figure out what went wrong? can I do a speed test to figure out if the speed drops, or if there is a voltage drop, or perhaps collect some error code from the USB controller registers?
3. I need the hub to carry all the serial data that gets converted to USB messages to the PC without a bottleneck; and when we consider that the serial speeds of my RS232 and RS422 devices are so slow (compared to USB... not my troubleshooting speeds...) I would think that any hub will do the trick. Having discovered this issue, I am curious why a hub with speeds much faster than the devices connected to it is acting as a bottle neck.

#################################################EDIT #2 If I plug the RS422 device direct into the PC, and the RS232 and Labjack USB devices into the USB hub (and then USB hub into PC), the Labjack U3 fails with an error.

Does this mean that I cannot use a USB hub?!?