battery on the 881U

Tutor

battery on the 881U

What on earth does the 881U aircard need a battery for?
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Message 1 of 5
Scholar

Re: battery on the 881U

Good question.  I looked this up when I got mine 881U and the Sierra site claims that the internal battery supplements the power from the USB port when extra power is required.  I assume that the power from a USB port may not be constant and so the battery.
 


Message Edited by bsmith15 on 03-10-2008 04:56:54 AM
Message 2 of 5
Master

Re: battery on the 881U

Typical USB port will typically deliver less than 2V of power, your device needs anywheres from 5 to 12 to power, hence the battery. 
Message 3 of 5
Tutor

Re: battery on the 881U

Please, people, if you don't know something about a topic don't try to answer it. USB ports provided regulated 5V power.
Message 4 of 5
Master

Re: battery on the 881U

The answers provided are mostly correct.  What Excaliber meant to say was that typical USB ports do not provide enough amperes.  (Nnot voltage.)  Devices are only allowed to draw up to 100mA initially.  You might be able to get more amperes if there aren't other devices drawing power on the same USB bus, but in my experience, this often causes the computer to crash or at the very least, for the OS to turn off that particular USB bus to prevent damage to the motherboard.
 
BTW, the information was also included in the manual for my 875U.  I don't know if it's still in the manual for the 881U, but as bsmith stated, it is available on Sierra's website.
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