Yes, it's a call connect confirmation. LG phones have had this for a long time in the form of a connect confirmation beep. I would ALWAYS turn this feature on back when I used to buy LG phones and I've really missed it since. It lets you know when your call has actually connected, that way you don't waste your time holding the phone up to your ear when the call never actually connected, or got dropped, or you forgot to press send or whatever. It's an awesome feature that I promise you will come to depend on and miss when/if it ever goes away.