Although you can split the two RX and TX mono channels in asterisk and record them together, that makes them binaural not technically stereo, I don’t think that what you desire can be done natively in FreePBX but
Although you can split the two RX and TX mono channels in asterisk and record them together, that makes them binaural not technically stereo, I don’t think that what you desire can be done natively in FreePBX but