Cruisers & Sailing Forums - View Single Post - Long-Distance WiFi Device

hellosailor · 25-03-2009, 17:50

Nick-
"If the active cable uses 50 mA you could still have 450 mA left for the device." Maybe in theory. But there will be voltage drop in the wires, more so in the long wires, and some devices will need to draw more amps to compensate for lower voltage. I agree with you that using a powered hub is the only safe (likely to work properly) way to push a long USB connection.
The USB spec is 500mA, if a computer does not provide that they cannot use the logo and trademark "USB" for the port, legally. I know some older laptops were fused at 400mA, but today, I think 500mA can be reliably expected. There are still funkier things going on in the hardware, i.e. the computer I'm using shows two USB controllers, each with 8 ports, but only one is connected to one controller, and two to the other, physically. Ghost ports?(G)

25-03-2009, 17:50	#97
hellosailor Registered User Join Date: Apr 2006 Posts: 3,997	Nick- "If the active cable uses 50 mA you could still have 450 mA left for the device." Maybe in theory. But there will be voltage drop in the wires, more so in the long wires, and some devices will need to draw more amps to compensate for lower voltage. I agree with you that using a powered hub is the only safe (likely to work properly) way to push a long USB connection. The USB spec is 500mA, if a computer does not provide that they cannot use the logo and trademark "USB" for the port, legally. I know some older laptops were fused at 400mA, but today, I think 500mA can be reliably expected. There are still funkier things going on in the hardware, i.e. the computer I'm using shows two USB controllers, each with 8 ports, but only one is connected to one controller, and two to the other, physically. Ghost ports?(G)