IC720.1 TRANSCEIVER TRANSMIT UNLOCK (FINAL PART) (IC-O2AT, IC-O4AT, IC-751, IC-720 Of course, in an emergency, anyone may use any type of frequency to attract attention. The emergency must be life- threatening or pertain to "immediate protection of property" before one would resort to using frequencies outside of the ham band. For mariners, the United States Coast Guard works closely with the high seas marine radio telephone service that is easily accessed via a geral coverage ham set modified to transmit on general coverage marine telephone channels at 4, 6, 12, 16, and 22 MHz. However, using ham radio equipment on telephone channels for routine phone calls is not allowed. Even though you may have a ship radio telephone license that allows you the use of marine telephone channels the license only allows Part 81 and Part 83 type-accepted equipment to be used for transmitting purposes - and again, Amaeur Radios don't meet this type acceptance. CONTINUED IN FILE IC720.3