The 127.3 Hertz encode tone can be programmed into most equipment by following the instructions in the operator manual.
Some manufacturers have web sites with programming information on line.
By programming 127.3 Hz into the tone decode circuit, your squelch will not open on signals other than those transmitted by the repeater. This is especially helpful during band openings and in areas with heavy interference. The tone is necessary on the Dames Point remote receiver due to sporadic interference on the 146.1 MHz input frequency from navigation equipment on ships traveling the channel beneath the bridge. The Starke site has required a tone for several months due to pager interference in that area.