Raymarine Ray230 Owner's Handbook Manual page 60

Operations
OR
Manually input the MMSI number with the numeric keypad, then press
the ENT key.
6. Press ENT again. A prompt appears on the display instructing you to
press the PTT switch.
7. Press PTT to transmit.
With manual input, MMSI
number would be displayed
Response
If a response is received after pressing the PTT switch, a receive-
confirmation message is displayed. After 5 seconds have elapsed, the
channel is switched to a communication channel and the Individual Call is
completed.
If no response is received for 3 minutes after pressing the PTT switch, a
prompt to press PTT appears once more. If the PTT switch is not pressed
within 15 seconds after the prompt appears, operation returns to the state
before the call.
PTT
ENT
Flashing
ENT
ACK
3 min
NO ACK
Scrolls every second
3-37
numeric
keypad
Flashing
5 sec
PTT