Hardware: A4
Firmware: 1.31 (had the same problem with 1.30, but not with 1.2x)
Shareport: 1.10
USB device: Canon Pixma MP500 Multifunction Printer
PC no.1: Desktop with Windows Vista Ultimate 64bit (SP1), CPU: Intel Q6600, Network adapter: Intel(R) 82566DC-2 Gigabit (Wired connection)
PC no.2: Acer laptop with Windows 7 32bit, CPU: AMD Turion Single-core, Network adapter: Atheros AR5005G (Wireless connection)
Problem: USB device works after router reboot for a couple of hours. After that it will be unable to connect. Sometimes it connects briefly before it then disconnects after a few seconds (but the USB device will still not work). If I then reboot the router again everything will start working automatically for a few hours. The time it takes before it stops working seems to be non-consistant, but it is never more than a day, usually much much less like 1-3 hours or so.
As you can see there are no hardware similarities to my PCs at all. Both my PCs have the same problem at the exact same time, and they also both work at the same time after router reboot. If one PC is on and the other is off when the problem occurs, turning on the other computer will not help (thus it can't be related to sleeping HW components). In other words: Whether or not the computers are on or off make absolutely no difference.
Rebooting the computers, the printer or shareport itself does NOT help. Only rebooting DIR-655 works.