KRLD does numerous live broadcasts and generally transmit an IFB signal (see here for an explaination on what that is --> Interruptible feedback - Wikipedia, the free encyclopedia ) to provide the remote broadcaster to receive their instructions, time their announcements, and allow the broadcast to contain feeds that don't originate from the remote location (such as commercials, news breaks, and even caller phone calls).
Originally this could've been handled using prearranged signals (e.g. click the on-air audio if you can hear me OK), commercial out-cues in their notes, and the remote broadcaster receiving the live signal (assuming their in range). Now that many, if not most, broadcasters have "HD" signals, this is no longer possible (why is explained below). Broadcasters now use another method to send this IFB such as a radio channel (like KRLD often does), a phone, or sometimes one of an FM station's SCA subcarrier channels.
To allow time required by to process and encode the IBOC "HD" signal the normal "non-HD" signal has a delay of about 8 seconds so the listener won't notice when their receiver switches between "HD" and "non-HD" modes due to signal fading or other issues (see here for details on this iBiquity Digital Corporation - Proper Time and Level Alignment ).