Wavecom W61PC V7.5.0 - Manual (Page 289)

WAVECOM Decoder W61PC/LAN Manual V7.5 SAT System  279
Message transfer from a mobile station to a LES is initiated by the MES finding the LES TDM frequency in-
formation in the NCS bulletin board. It then retunes to this TDM and synchronizes to the TDM frame. The
MES finds a free signaling channel slot by reading the LES TDM bulletin board information and transmits
an assignment request to the LES. The LES informs the NCS that the MES is busy. It then sends an as-
signment packet to the MES containing, message channel frequency, slot number and LCN. The MES re-
tunes and starts transmitting its message.
SAT-C is mainly used in maritime communications, but is also widely used for long distance truck fleet
management where the trucks are polled and then return position information from a GPS receiver. The
system also finds its use in the remote control of pumping stations or remote data acquisition.