[Packet] Correction...Packet] GPS power???

Thu, 5 Dec 2002 19:35:07 -0500

Does anyone know what the max CURRENT a USB or keyboard port can safely
supply ??

I had a few laptop connected devices over the years that needed 5V.
Parallel port network adapters, gaming adapters, etc.  If really low power
devices, they could be powered by a keyboard adapter plug that spun off the
5V to a pin connector for the device.  Much better than carrying yet another
wall-wart.

Road warriors WILL make equipment decisions based on not having to carry yet
another wall-wart supply !!  The typical laptop power brick is already
115/230-50/60HZ and supplies a fair amount of both 12 & 5V power.  Some
charger adapters from these would be very much welcomed.

I traveled extensively until the late 90's and was always on the lookout for
things that would lighten the load.  Having to carry a laptop, briefcase,
PDA, Pager, cellphone or two, some work related radio and test gear, AND  a
few days clothing, certainly limited the personal radio gear I could truck
around with.  I felt like a NASA engineer every time I discovered a way to
leave an 8oz device behind.

Frank

 ._._.
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, December 05, 2002 7:10 PM
Subject: RE: [Packet] Correction...Packet] GPS power???

> Unless they've changed the spec, the power supplied on USB is not of a
specific fixed voltage, such that for virtually all applications, a voltage
regulator would be required by any device deriving its power from the cable.
I don't recall the exact range of voltages that can be supplied but I think
8 to 20 VDC is in the right range.  I beleive the PS/2 keyboard connector is
spec'd at 5 VDC, as I don't recall a voltage regulator in any of the
keyboards I've taken apart.  And the keyboard does need something to run the
keyboard scanning controller CPU and LEDs.
>
> 73, Bob, KD7NM

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