BCD996T REC out issue

[mojo3120]

I've got a BCD996T with a 3.5mm audio cable run from the scanner REC out to the aux in on a stereo in another room. The remote audio will play the first 5-10 seconds of a transmission and then cut out. The audio from the scanner does not do this, only the remote audio. Any ideas what might be going on? Thinking about trying the EXT Speaker jack (to the remote stereo aux in), would I need to include some type of isolation transformer to do that?

[Will]

Add a blocking capacitor.