This thread is not part of TTT, it is Tetra Network Monitor (TNM if you will)Good night!
I've been noticing something that happened in the early versions of "TTT"
In the Calls panel, GSSI and ISSI appear, but they do not have audio and are not in bold. It looks like it's not active. I noticed that when this occurs it has audio on TTT and on the radio.
It's not often that happens!
Thanks and waiting for new versions.
Download and use latest version of TNM.
Sounds like the call that appears in Call list is out of range of the setup you are using. Since you provided no details of it I can't help further.
Latest version (v126.96.36.199) can be found here: Download