Post has attachment
 
"I'm running DIAL on a R-Pi2 into a modified USB fob for connection to my repeater. Everything seems to load and be configured fine, but I can't get the fob PTT to trip. I believe the PTT FET is driven from the red LED on the fob (pin13) and I can't get a new un-modded fob to cycle the red LED either. Audio courtesy tones and hang time and receive audio passes the in/out of the fob during COR, just NO keying. Ideas where the config is unright? "

OK, the red LED on the fob is NOT the red LED shown in the mod diagrams, it is the fob "mute" status. PTT LED is ADDED to the CM108/13 pin that is unused on the fob to bring out local PTT status. Making this trace cut and wiring the onboard "mute" LED to pin 13 brings out that status. 
Many thanks to Bob KK6ECM for the mod pix and Steve N4IRS for explanations. The fob runs nicely now!
FORWARD!
Photo

Post has attachment
Just came across a $35 kit combining a CM119 USB IC and controls for USB to radio interface. It includes an option to disable PTT with loss of "heartbeat".
http://www.masterscommunications.com/products/radio-adapter/ra35.html

Post has attachment
If you are building an Allstar Link Audio interface: 
CM108 USB fob. Confirmed CM108 and accessible chip for modification. Perfect!
Looking at the board carefully, it looks like the mic tip and ring are wired together and removing 0-Ohm chip resistor R6 opens the 4V mic Vbias line from CM108 pin 25, leaving mic T+R pins connected to CM108 MICIN pin 27 through a chip cap. Mic T-R pads are on J3 on the red LED side of the board if the jacks are removed.I just confirmed R6 does indeed remove the 4.5V mic bias.
http://www.ebay.com/itm/291156304476

Post has attachment
Photo

I currently have an IRLP Node that I want to convert to AllStar, but I don't want to get rid of IRLP. Is there any way to have a node that does AllStar, IRLP, and Echolink?
Wait while more posts are being loaded