Thanks for your useful comments! So, I guess the first thing to try is getting an external powered USB hub, and try it again (presuming that it delivers at least 5 V). regards wim > Greg K-H wrote: > >> On Wed, Jan 21, 2009 at 09:30:59PM +0100, Wim de Vries wrote: >> > OK. Thanks. >> > I have measured the voltage, with the device connected: >> > on my (Win) PC 5.10 V >> > on my (Linux) laptop: 5.12V >> > on the asus eee pc: 4.96V >> > Do you think that difference is a problem? >> >> Yes, that is on the lower bound of what the device is expecting, so it >> could cause problems. > > 4.96 V would appear to be well within the bounds of the specification. > USB2.0 paragraph 7.2.2 (page 175) says: > > * The voltage supplied by high-powered hub ports is 4.75 V to 5.25 V. > * The voltage supplied by low-powered hub ports is 4.4 V to 5.25 V. > > There is a diagram, Figure 7-47, on the same page, which details the > allowable voltages at various points in the USB power distribution > system. > > Dave > > > NICE CTI Systems UK Limited ("NICE") is registered in England under > company number, 3403044. The registered office of NICE is at Tollbar Way, > Hedge End, Southampton, Hampshire SO30 2ZP. > > Confidentiality: This communication and any attachments are intended for > the above-named persons only and may be confidential and/or legally > privileged. Any opinions expressed in this communication are not > necessarily those of NICE. If this communication has come to you in error > you must take no action based on it, nor must you copy or show it to > anyone; please delete/destroy and inform the sender by e-mail immediately. > > Monitoring: NICE may monitor incoming and outgoing e-mails. > > Viruses: Although we have taken steps toward ensuring that this e-mail and > attachments are free from any virus, we advise that in keeping with good > computing practice the recipient should ensure they are actually virus > free. > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html