In a telecommunications system, a test point, i.e., a point where a signal may be inserted or measured, and for which the nominal power of a test signal is specified. Note 1: In practice, the abbreviation, TLP, is usually used, and it is modified by the nominal level for the point in question. For example, where the nominal level is 0 dBm, the expression 0 dBm TLP, or simply, 0TLP, is used. Where the nominal level is -16 dBm, the expression -16 dBm TLP, or -16TLP, is used. Note 2: The nominal transmission level at a specified TLP is a function of system design and is an expression of the design gain or loss. Note 3: Voice-channel transmission levels, i.e., TLPs, are usually specified for a frequency of approximately 1000 Hz. Note 4: The TLP at a point at which an end instrument, e. G. , a telephone set, is connected is usually specified as 0 dBm.