This read-write yes/no setting controls whether DTMF detection on this port also considers signal energy in addition to tone frequencies. The desc notes that in some cases DTMF detection only works correctly if energy detection is turned off, so this gives an administrator a way to work around detector false negatives or false positives. For example, if this port intermittently fails to register dialed digits, an administrator might toggle this object to no(2) to see if disabling energy-based detection resolves the missed digits.