Raymarine Ray54 - Manual (Page 46)

36 Ray54 VHF Radio
6. Push in the CH knob to accept the selection.
7. Push CH knob again to send the Individual Call.
The Individual Call is transmitted on channel 70, and then the radio tunes
to the original channel and waits for acknowledgement. During this
period you are still able to receive calls.
Note: Pressing PTT at any time before an ACK is received cancels the Indi-
vidual Call.
When the acknowledgement is received, the Ray54 automatically switches
to the selected working channel and sounds a DSC Call alert ring. Press any
key to mute the alert ring. It shuts off automatically after two minutes.
8. Press PTT to communicate on the specified channel.
If no acknowledgement is received within 3 minutes, the radio prompts
you to resend the call.
If you do nothing for 2 minutes, the Individual Call is cancelled and the
radio reverts to the original channel.