This read-write yes/no setting enables the voice codec on this port to fall back to an 8 Kbps rate using single buffering when conditions require a lower bandwidth mode. Enabling it gives the port one additional lower-rate fallback option to preserve call continuity rather than dropping the call when the primary rate cannot be sustained. For example, on a link experiencing congestion, enabling this object lets calls degrade gracefully to 8 Kbps with single buffering instead of failing outright.