Furuno FELCOM 16 Operator's Manual page 17

Types of MES
There are three types of MES: class 1, class 2 and class 3. This FELCOM 16
is a class 2 MES.
Class 1:
Class 2:
Class 3:
1) Transmits messages to LES
2) Receives messages from LES
1) The functions of class 1 plus operation as an EGC receiver
when not transmitting or receiving.
2) EGC-only receiver
The function of class 1 plus simultaneous operation as an
EGC-only receiver.
INMARSAT C SYSTEM
xv