Please excuse previous post,It just dawned on me what it's for.
Close Call™ RF Capture Technology - Instantly detects and tunes to nearby transmissions with no additional programming.
Close Call Do-Not-Disturb - Checks for Close Call activity in between channel
reception so active channels are not interrupted.
Close Call Temporary Storee - Temporarily stores and scans the last 10 Close Call hits so that you can continue to monitor activity on those frequencies, even after you are out of Close Call detection range.