[Elecraft] K3s USB sound card not receiving MMTTY audio

[Mike Dodd]

I have had the built-in SUB sound card in my K3s working with MMTTY in 
AFSK A mode in the past, but now it does not produce TX tones when MMTTY 
transmits.

MMTTY is set up to use the USB Audio Codec in RX and TX, and can decode 
RTTY signals. When I click the TX button, the K3s goes into transmit, 
but produces no output (ALC is zero).

If I set MMTTY's Transmission sound card to the PC's built-in speakers, 
I hear the tones when transmitting, so MMTTY is producing them. It just 
doesn't send those tones to the K3s USB sound card.

What am I missing? Again, this has worked many times in the November 
2021 WAE RTTY contest.

Thanks.

--- Mike N4CF