Dual Dell 1908fp Monitors - Different USB Behavior

Hi Elgrandeburro,

As per the manual the USB interface of the monitor works only when monitor is powered 'ON' (or in Power Save Mode). Switching your monitor 'OFF' and then 'ON' would re-enumerate its USB interface; attached peripherals may take a few seconds to resume normal functionality. So there could be a possibility that the other monitor is going in power save mode that is why you are able to use the USB ports on that monitor. In order to assist you in a better way I need to know the following things:

• How are you checking the functionality of the USB ports when it is off?
• Which devices have you connected with the monitors?
• May I know the cables you have used with these monitors to set up Dual monitors?

Please reply with the findings

Hi Chinmay, thanks for your quick reply.

Here's the information you requested.  This entry is for the monitor whose hub remains powered:

• Cabling:
  • Video is connected to my computer via its DVI connection and a DVI cable.
  • USB is connected via a usb cable.
  • Both cables above, run straight from monitor to computer, without any intermediary devices, extensions, or adapters.
• I am checking the USB port functionality in the following way:
  • Starting Condition:  Monitor is powered on and connected to my computer, with both video and usb cables.
  • Plugged in the usb hub on the monitor, is a usb flash drive in one port, and a Yubikey in another port.
  • Next, I turn off the monitor, by using the monitor's power button.
  • Testing: I then use a directory manager to manipulate files on the flash drive; also, the drives led indicator remains lit.
  • Testing:  For the Yubikey, I am able to make it generate password data as it is designed to do; also, its led indicator light remains lit

Hi,

Thank you for your quick response. I understand your concern and will take care of the issue for you. In order to assist you further, I would request you to provide me the monitor serial number (PPID number).  

You can find the monitor PPID at the rear of the monitor. There will be a sticker with barcode serial number label. 

Please reply with the information.

Sure thing, here they are:

• Monitor with active hub PPID:  CN-0G554F-64180-84B-1NPH,  Rev: 00
• Monitor with inactive hub PPID:  CN-0UW042-64180-793-2AVH,  Rev: 00

Hi Elgrandeburro,

Thank you for the reply. It seems from the serial# that both of the monitors are from different manufacturers. I am in touch with the product group team to get the update on this issue. I appreciate your patience and will keep you posted. 

Hi Elgrandeburro,

I am researching upon the issue. You can try these steps below to check if it makes any difference:

If you are connecting two monitors to two towers then, the try connecting the inactive hub monitor on both the towers and check for the output and vice versa. You can try swapping the monitors and cables to check the output.

Please reply with the information.