Zero dBm transmission level point

Zero dBm transmission level point (0 dBm TLP): In a communication system, a point at which the reference level is 1 mW, i.e., 0 dBm.

Note: The actual power level of the communications traffic is not necessarily 0 dBm. It is usually below the reference level. The reference is for system design and test purposes. Synonym zero transmission level point.

Source: from Federal Standard 1037C