Standard Horizon Quest GX1255S Owner's Manual page 15

CALL/SET Key
The CALL/SET key functions as the enter key.
Secondary use
Press the CALL/SET key to access the DSC OPERATION menu. The
INDIVIDUAL and ALL SHIPS CALLS functions can be accessed from
the DSC OPERATION menu.
Press and hold the CALL/SET key to access the RADIO or DSC setup
menu. The following functions can be accessed in the menu.
RADIO SETUP MENU
DSC SETUP MENU
DISTRESS Key
Used to send a DSC Distress Call. To send the distress call see section
6.2 (Sending a Distress Call).
UP and DOWN Keys
The UP and DOWN keys are used to select a desired channel and to
select items in the DSC OPERATION and SETUP menus. The UP or
DOWN key on the microphone can also be used to select channels.
GX1255S Page 13