[arm-allstar] Yet another USB FOB Modification

Mark Herson, N2MH n2mh at n2mh.net
Sat Nov 15 11:25:44 EST 2014

Yet, yet another comment on FOB mods...

I've done a bunch here on pc prototype board. One thing I always like to
see is some LED's to indicate what is going on.

In addition to the green heartbead LED, I also include a red LED to
indicate PTT and a yellow LED to indicate COR coming into the fob.

The red LED needs another transistor in parallel to the usual PTT LED.
This keys the red LED which is then connected to +5 VDC through a current
limiting resistor.

The yellow LED is connected from the incoming COR line through a current
limiting resistor to +5 VDC. This limits the incoming COR to an active
ground from the radio equipment. Fortunately, this protects the sound fob
from an incorrect COR condition if the radio is turned off or otherwise
disconnected from the FOB.

+5 VDC is picked up from the sound fob.

This whole topic reminds me of YAPP from the early days of packet radio.
YAPP was a file transfer protcol customized for packet radio. YAPP stands
for Yet Another Packet Protocol :-)

73, Mark, N2MH
Allstar Node 40831
ACID plus 2 BBB's and counting...

> Date: Sun, 9 Nov 2014 02:11:25 -0500
> From: Doug Crompton <doug at crompton.com>
> To: "arm-allstar at hamvoip.org" <arm-allstar at hamvoip.org>
> Subject: [arm-allstar] Yet another USB FOB Modification
> Message-ID: <BLU172-W299469D7812B52ECE86A28BA830 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
> Here is a link to my modification of the USB FOBS recently noted on this
> list and available from ebay at $24 for a lot of 10. I will be adding
> this link to the BBB web Page.
> http://crompton.com/hamradio/usb_fob_modification/
> 73 Doug
> http://www.crompton.com/hamradio

More information about the arm-allstar mailing list