Raymarine Ray230 Owner's Handbook Manual page 126

Appendix
Important Notice
The Canadian frequency mode is not legal for use while operating in U.S. waters.
Notes:
1. For channel 13, output power is fixed at 1 watt (low power) by regulation. In
an emergency, you can override to high power by pressing and holding PTT and
then pressing the MON/ 1/25 key on the base station. Output power is increased
to 25 watts while both keys are pressed. After MON/1/25 is released, power returns
to 1 watt.
2. For channels 15, 17, and 77, output power is fixed at 1 watt only. Transmission at
high power is not permitted.
3. Channel 70 is used for Digital Selective Calling (DSC) only and is not available
for voice transmissions. Channel 70 does not appear on the display.
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