USB Bandwidth Exceeded with GT-1900u

Our friends and family who are reading this blog will need to excuse me for a minute (or rather a post) while I address the internet. I tend to do this from time to time, especially when I’ve found a fix for a technical problem that I want to share with others. That is the case here.

The GT-1900u is a combination VoiP/Dect phone from a company called Perfectone.

The first thing I want to mention is that if you get an error about “USB Bandwidth being exceeded”, don’t ignore it like I did, this is a problem. While I’m talking about the problem, in my case this problem was evidenced by three beeps (indeed, 3 beeps) when I tried to call numbers from the phone using Skype.
Basically what the story is, is that another device is hogging the bandwidth to the motherboard, and the device (in my case the phone) doesn’t have enough bandwidth to operate.

So how do you fix the problem?

The fix most commonly suggested on the forums is to get one of the devices off the PC. Usually (and in my case) the offending device is the USB ADSL modem, so they suggest replacing it with an ethernet version.

However, I wasn’t happy with that option so further investigated. It turns out various modems, including my Speedtouch 330, have two modes, isochronous and bulk. The ISO mode is to optimise speeds over 4mb/s and bulk is the best for speeds under.

It turns out that one of the side-effects of ISO mode is that it uses more of the USB bandwidth than bulk. I haven’t been getting 4mb most of the time anyway, and it’s more than I need, so I decided to switch back to bulk.

I’m sure there was an easier way, but I just uninstalled the modem and reinstalled, selecting <4mb/s this time instead of >4mb.

Problem solved. Please comment, or link this article if it solved your problem.

Update 1:  We still occasionally (after this post) experienced the three beep problem so replaced our USB ADSL Modem with an ethernet version.

Update 2:  We’re still occasionally experiencing the three beep problem, so are pretty stuck.  I suspect it may be because the device is still draining too much power, perhaps my USB connection to the motherboard is not connecting properly or there is some other reason.  Anyway, I’m keeping the phone as it works sometimes.  Let me know if you find another fix.