Comtech EF Data RCF6001 - Manual (Page 11)

RCF6001 Satellite Terminal Description
TM082 - Rev. 1.0 Page 1-3
The topology of the network in both of these broadcast examples would typically be called a “Star” network.
As shown in the Figure below, the shape of the configuration is drawn with the central “Hub” as the center
of the star and the remotes as points of the star. In both cases the transmit frequency and other parameters
are shared by the receiver of all the remotes.
1.1.3 DAMA (Demand Assigned Multiple Access)
Suppose that we wanted to simulate a telephone network with a virtual switch between modems carrying
digitized voice information. We might use a central computer to assign a pair of frequencies for any
conversation and send this connection information to the proper sites to set up the connection. In this
application a new network configuration is usable. That is a “Mesh” network where any of the voice
modems at any site can be programmed to link with any other modem. The resulting link diagram looks
like a mesh of interconnects.
Since the frequencies can be assigned on demand, the network is then called “Demand Assigned, Multiple
1.1.4 TDMA (Time Division Multiple Access) Remote Site Application
In a TDMA network, the central Hub continually transmits a stream of outbound data containing information
for multiple remote sites, while the remote sites transmit back to the Hub on a timed basis. Each of these
remotes is said to “burst” its information back on a specific frequency. This may be the same inbound
frequency for all sites. Each of the remotes is responsible for accessing its own information from the
outbound data stream by reading the address assigned to specific parts of the data. The TDMA network
usually looks like the Star network shown above.
Star Network Configuration
Hub
Remote
C
Remote
E
Remote
D
Remote
A
Remote
B