Raymarine Ray54 - Manual (Page 23)

Chapter 3: Getting Started 13
Press and hold CALL/MENU to select Menu Mode, which is used to set up the
radio. The menu structure is outlined in the following drawing. Menu
operations are fully described in Chapter 6.
10. HILO/USER
Press and release this key to toggle the transmit power from HIGH to LOW.
Press and hold to select User Channel Mode, which displays only the
channels that you have saved to memory. User Mode is described in Section
4.13.