Line out normally would be an audio out to a recorder or amplifier. Don't have a Uniden so can't say for sure what they provide. I was referring to a connection for external speaker to use instead of the internal speaker, it would silence the internal speaker when external speaker plugged in (like a shoulder speaker)
Already on the scanners...I have an external speaker on my WS1095 in my mobile install. Non-amplified, just a speaker - is controlled by the volume on the scanner.