sMRT Crewguard User Manual v1.1
MRT Ltd. © 2014
7
6.1 POWER
– Turns unit on and off.
6.2 TONE DETECT –
Enable/disable
In this mode the Crewguard only identifies and responds to a signal from a
Sea Marshall® SOS Alerting Unit (PLB). When an SOS signal is received the
unit activates both its internal and external alarm or other external devices
connected to the unit.
63 FREQUENCY -
Set to 121.5MHz when the power ON/OFF button and
or reset button is pressed.
6.4 TEST -
Select test frequency as required (121.65 or 121.775MHz).
NOTE: the unit will automatically default back to 121.5MHz after 20 minutes.
(Your unit if required may be programmed to default to 121.65MHz).
6.5 RESET
– Press this button to cancel the external alarm and reset the unit
6.6 VOLUME
– HIGH / LOW – NOTE these buttons can be used to control
the brightness of the display LEDS. To do this press and release the
POWER button so that all LEDs are lit. Use the VOLUME buttons to adjust
the LED brightness.
6.7 RRSI
– Received signal indicator. (Red LED in middle of SOS logo)
6.8 RSSI
– Received Signal Strength Indicator – 4 Green LEDs
6.9 Plug wiring
If for any reason you are unable to affect your rescue contact the Coast Guard and tell
them you have a man in the water wearing a 121.5MHz PLB.
Black 1
Relay Contacts
Black 2
0V DC Negative
Black 3
2V DC Positive
Green / Yellow
Relay Contacts
