Resending since my initial post has been pending moderation for 2 days now and got no reply from the list owner email. I have modified an HT to bring out the receive LED signal and use it as the COR input to a DMK URI. It is a digital signal as viewed on a scope (i.e. very short slope in the transitions) This seems like it would work well and it does on strong signals. But on marginal signals where the LED may blink on and off quickly (like during picket fencing), it seems to confuse the URI (or the software) were it will start off good, but then a quick dropout of the COR signal will cause the software to no longer detect carrier, even though the signal on the COR input has been restored. Even if the input is solid high (or low in my case, I'm using usbinvert) it will not detect a carrier until there is another dropout of adequate time to "reset" it. I've tried putting a simple RC on the input but it didn't really help much. Seems the URI (or software) needs a significant minimum time between transitions to properly detect them, long enough that it would delay the carrier detection too much without a circuit more complex than an RC (i.e. something that would allow instant keyup, but delay the key down.) Linked is a scope image. https://lh5.googleusercontent.com/-CsJ9autUTAE/VCWK-uNJJpI/AAAAAAAAPSM/VsVvb... Carrier was detected until this signal dropout event. Ch A is my RC filtered signal sent to the URI, Ch B is the signal out of the radio. Carrier was not detected after the 5th dropout even though the signal remained low. Anyone ever experience this and/or have ideas on how to fix it? Thanks. Mike KF7MBK