Montreal Protocol (1973) and the international agreement signed (1985 & 1987). The treaty is structured around several groups of halogenated hydrocarbons that deplete stratospheric ozone. All of the ozone depleting substances controlled by the Montreal Protocol contain either chlorine or bromine (substances containing only fluorine do not harm the ozone layer). Some ozone-depleting substances (ODSs) are not yet controlled by the Montreal Protocol, including nitrous oxide (N2O) For a table of ozone-depleting substances controlled by the Montreal Protocol see: For each group of ODSs, the treaty provides a timetable on which the production of those substances must be shot out and eventually
QSK operation (full break-in) QSK operation must ensure that their radio equipment includes the hardware capability for radio frequency antenna switching that operates rapidly enough to allow listening between signals at the appropriate Morse code sending speeds with appropriate lifetimes and reliability. QSK operation (full break-in) "Turning over" a communications channel is the change in communications protocol transmission status that occurs when a transmitting station releases transmitting control of a communications channel thus turning it over to allow another station to transmit. QSK or full break-in operation is one of several techniques and protocols for turning over control of a Morse code radiotelegraph communications