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INDUSTRIAL MODEM RF115
Figure 15-3 shows a link with two repeaters between the master and slave. With two
repeaters, there is clearly more flexibility in getting around obstacles and greater
total range is possible. Once again, it would be desirable to use external
omnidirectional antennas with the repeaters, and attaching a Yagi to the master
and slave would increase the range of the link.
When two repeaters are used, there is no further degradation in the RF speed of
the link.
Figure 15-3. Link with Two Repeaters Between the Master and Slave.
Figure 15-4 shows a setup where a master routinely calls a number of slaves at
different times. The master is communicating with a modem designated as a
slave/repeater, which is connected to a remote instrument in the field. Since this
instrument is placed in an elevated location, the modem may also be used as a
repeater when it is not used as a slave. At any time desirable the master may call
any of the slaves, establish a connection, and retrieve and send data.
Figure 15-4. Master Calling a Number of Slaves.
Master
Slave
Slave
Repeater
Slave
Slave/
Repeater
Master
Repeater
Slave
Repeater
Summary of Contents for MD3310-R2
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