remoted up to 1,500 feet (455 meters). A low gain antenna is used during mobile operations. A high gain
antenna is used during stationary operations.
b. The AN/GSC-40, AN/GSC-40A(V)1, and AN/GSC-40A(V)2 are rack mounted CGCPTs.
These
terminals are installed in CPs and configured according to the physical limits of the site.
2. A high degree of network flexibility is accomplished by using a time division multiple access (TDMA)
control structure and a CGCPT. This technique allows communications to be executed on a time-shared basis
between other terminals within the theater network. The terminal can operate in the random or time division
multiplexing (TDM) modes. The random mode of operation allows the user to enter the TACSAT
communications network on a random basis using an open selected channel.
LEARNING EVENT 4: CONTROL AND MANAGEMENT
1. The control and management procedures discussed here pertain to the communications between AN/GSC-
40(V) and AN/MSC-64(V). The AN/GSC-40(V) performs the network control function (NCF) for a net of
AN/MSC-64(V) FTs.
2. The NCF, normally located within a CP, performs the following subnet control actions:
Transmits network timing synchronization message for initialization of a terminal entering the network
and for retiming all receivers within the network.
Transmits satellite operating mode for use by FTs.
Transmits crypto-control data.
Performs message preemption to allow transmission of a message with a higher precedence.
In stressed mode, identifies each frame, establishes priorities, and dynamically assigns use of next slot.
3. The FTs perform the following control actions:
Acknowledges/transmits messages.
Loads and monitors the synchronization code.
Selects transmit channel and time slot.
Monitors emergency action message alarm.
6-3
SS0031
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