Canadian Mac Forums at ehMac banner
1 - 15 of 15 Posts

·
Registered
Joined
·
238 Posts
Discussion Starter · #1 ·
Looking to buy the new Mac keyboard because it has 2.0 USB ports but when I read the reviews on Apples website people complain that the USB ports don't work as they should. Anybody aware of this, is it just a minor glitch.
 

·
Premium Member
Joined
·
4,415 Posts
What problems do people seem to be having?
From what I've heard, people seem to have problems with speed -- the ports on the Apple Keyboard acting kinda like "USB 1.5" :D

They're apparently just slower than the actual USB 2.0 ports on the computer -- but faster than the old USB 1.1 ports on the old apple keyboards.
 

·
Registered
Joined
·
566 Posts
i loaded 175 8MB photos off my slr last night through the keyboard port on mine and they were screeming fast. So no problems here. By the way dont ever expect to get the theoretical maximum throughput on USB 2.0. Just because it is supposed to be able to do 32MB/s doesnt mean it can. USB is not a very good protocol for data transfer, it was designed for input devices like keboards, mice and joysticks. Now firewire can hit very close to its theoretical max, but not usb even if its all alone on a port with its own bus.
 

·
Premium Member
Joined
·
9,103 Posts
fyrefly got it, people where having problems with the speed of the usb ports on the new keyboard. They weren't 2.0 as Apple advertised. I should have been more specific.
The Apple Store (Canada) - Apple Keyboard
I read all six pages of comments on the link you provided.

Nobody had any problems with the speed, at least nobody mentioned it.

What a number of people were complaining about was that the USB 2.0 ports didn't work with their ipod and some KMV devices because there wasn't enough power.

Big difference between speed and power.

I don't understand how people expect the USB ports on a keyboard to be powered unless there is some external power supply connected to the keyboard to provide power in the first place. Every powered USB hub has an external supply of some sort, if there is no external supply, the USB ports of that hub are not powered but they can still be USB 2.0.
 

·
Premium Member
Joined
·
4,415 Posts
What a number of people were complaining about was that the USB 2.0 ports didn't work with their ipod and some KMV devices because there wasn't enough power.

I don't understand how people expect the USB ports on a keyboard to be powered unless there is some external power supply connected to the keyboard to provide power in the first place. Every powered USB hub has an external supply of some sort, if there is no external supply, the USB ports of that hub are not powered but they can still be USB 2.0.
Hahaha. I totally agree with you -- but still:

http://www.apple.ca/keyboard/ said:
Two USB 2.0 ports provide high-speed connectivity for your iPod, Mighty Mouse, digital camera, and other USB-based electronic devices. Yes, we did think of everything.
People expect it 'cause Apple advertises it. :)
 

·
Premium Member
Joined
·
3,882 Posts
Looking to buy the new Mac keyboard because it has 2.0 USB ports but when I read the reviews on Apples website people complain that the USB ports don't work as they should. Anybody aware of this, is it just a minor glitch.
Here's a quote from a web review (link below)...

"Oh sweet! I can use my iPod on my keyboard now? Awesome! I plugged mine in and guess what showed up on my Macbook and iMac? “USB Low Power Notice.” Thanks for lying out your ass Apple. I’ll stick to using the keyboard for my mouse and a card reader."

http://crunchgear.com/2007/08/17/the-new-apple-keyboard-reviewed

:rolleyes:
 

·
Registered
Joined
·
236 Posts
Every powered USB hub has an external supply of some sort, if there is no external supply, the USB ports of that hub are not powered but they can still be USB 2.0.
I have a small USB hub that is also powered, no external power supply (I know because I have used an external HDD that uses 1 USB connection, if it was low-powered it would need a 2 USB plugs) This hub has a little light on it that says when it can power devices and when it can't.

wikipedia said:
A bus-powered hub is a hub that draws all its power from the host computer's USB interface. It does not need a separate power connection.However, many devices require more power than this method can provide, and will not work in this type of hub.

In contrast a self-powered hub is one that takes its power from an external power supply unit and can therefore provide full power to every port. Many hubs can operate as either bus powered or self powered hubs.
 

·
Premium Member
Joined
·
9,103 Posts
Bus-powered and self-powered is terminology created by USB Org. - in that sense official.
But the terminology that is used 'on the street' is powered and unpowered.
Powered = self-powered, each USB port can provide at least 500ma of current
Unpowered = bus-powered, each USB port can provide at least 100 ma of current

I guess the term 'unpowered' comes from the fact that there is no separate power supply required for these USB hubs, they take the 500ma from the upstream port and divide it into 4x100ma for the USB hubs.
Interesting side comment - the 'expensive' unpowered (or bus-powered) hubs have circuitry to divide the 500ma from the upstream port equally to the four downstream ports, so each port will only get 100ma and a bit.
The "inexpensive" unpowered (or bus-powered) hubs don't have that circuitry and they will supply whatever they can to any one port. So if a port requires say 200ma, an 'inexpensive' USB hub will supply that to the one port (and proportionally less to the others) whereas an 'expensive' hub that meets all of the USB specs won't (it's limited to just over 100ma.
This means an 'inexpensive' USB hub may work better and for example drive a device that a 'expensive' hub may not.

As to the Apple keyboard problem - they seem to follow the USB specification and limit the current to 100ma or slightly more.
I noticed that even on the existing keyboard - had a Logitech mouse plugged in rated at 100ma and it would occasionally lock up - plugged the mouse directly into the Mac and the problem disappeared.
I could run an Epson printer off the keyboard USB hub no problem because it wasn't drawing any significant amount of power.

Back to the Apple keyboard - with 100ma of current available per port, that's enough for the MightyMouse and the Camera, but not for some ipods.
I was trying to find the charging current required for ipods, but there are a lot of different ones and they all use different Lithium-Ion batteries. Couldn't find the charging rate anyway, only the capacity in mAh.
Typical trickle charge is 1/10 of the capacity, based on that some ipods will get enough power from a bus-powered USB port, others won't.
iPod and iPhone Battery and Power Specifications
 
1 - 15 of 15 Posts
Top