Re: [Elecraft] USB Cable Power Requirements
It is a low power USB device, because it does not power anything in the rig. The only connections are TX data, RX data and common (ground)--see page 5 of the KX3 manual. It won't strain either of those USB hubs. --Tim (KR0U) I bought a Mac with only four USB ports and am going to purchase a powered hub. One of the hubs offers seven ports, but only 2 A for all the ports. The four-port version offers a full 500 mA per port. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] USB Cable Power Requirements
Joel, I have a MacBook Air that has only ONE USB port. I have a Targus non-powered USB octopus plugged into it. Into that I have plugged the KUSB cable, a Mac USB keyboard, a Newer Technologies 1TB external hard drive, and a USB cable for my SignaLink USB device. And, on occasion, I plug my AIM-4170 antenna analyzer into it. You may not need a powered hub unless you have some other power-hungry device to run. Jim / W6JHB On Dec 31, 2012, at 7:25 AM, Joel Black wrote: Are there any power requirements for the KUSB cable? I have looked all over the Elecraft page. If the answer is there, I cannot find it. I bought a Mac with only four USB ports and am going to purchase a powered hub. One of the hubs offers seven ports, but only 2 A for all the ports. The four-port version offers a full 500 mA per port. Thanks, Joel - W4JBB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] USB Cable Power Requirements
AFAICT, there is no specific power requirement mentioned for the KUSB (nor for the Sabrent equivalent that I purchased at my local Tiger Direct store), which means that, probably, it's safely within the 100mA power limit imposed by the USB spec. BUT, you should be aware that the Signalink USB *does* require an external powered USB hub, because it draws close to 500mA, and says so in its specs, etc. I'm running it and the Sabrent off of a 7-port hub that I bought at Staples (yes, ouch... - do shop around if you can, and balance availability vs. shipping costs, etc.) and have also run, at the same time, an SCS PTC-ii USB off of that hub as well as a PS/2 keyboard and mouse when I had it all attached to an Acer netbook. (These days, I'm running just the Signalink and the Sabrent to the iMac). I have had problems with the mini-USB plug on the hub loosening up on me, however, so if you have time to shop around, it's something to closely inspect. HTH, 73 and Happy New Year Brandy, N1HO From: Joel Black w4...@charter.net To: elecraft elecraft@mailman.qth.net Sent: Monday, December 31, 2012 10:25 AM Subject: [Elecraft] USB Cable Power Requirements Are there any power requirements for the KUSB cable? I have looked all over the Elecraft page. If the answer is there, I cannot find it. I bought a Mac with only four USB ports and am going to purchase a powered hub. One of the hubs offers seven ports, but only 2 A for all the ports. The four-port version offers a full 500 mA per port. Thanks, Joel - W4JBB _ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] USB Cable Power Requirements
I have been running my SignaLink USB directly from my MacBook Pro for two years now with no problem. I checked the Wikipedia page for USB http://en.wikipedia.org/wiki/USB and I think it has an explanation: Power ... A unit load is defined as 100 mA in USB 2.0, and 150 mA in USB 3.0. A device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0; 6 (900 mA) in USB 3.0. ... Every device functions initially as low-power but the device may request high-power and will get it if the power is available on the providing bus. ... A bus-powered hub initializes itself at 1 unit load and transitions to maximum unit loads after it completes hub configuration. Any device connected to the hub will draw 1 unit load regardless of the current draw of devices connected to other ports of the hub (i.e. one device connected on a four-port hub will draw only 1 unit load despite the fact that more unit loads are being supplied to the hub). A self-powered hub will supply maximum supported unit loads to any device connected to it. ... The MacBook Pro USB ports act as a powered hub. The SignaLink probably won't work on a unpowered hub. Cheers - Bill, AE6JV On 12/31/12 at 8:21 AM, n...@yahoo.com (Bayard Coolidge) wrote: BUT, you should be aware that the Signalink USB *does* require an external powered USB hub, because it draws close to 500mA, and says so in its specs, etc. --- Bill Frantz| If the site is supported by | Periwinkle (408)356-8506 | ads, you are the product.| 16345 Englewood Ave www.pwpconsult.com | | Los Gatos, CA 95032 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
