MDS 05-3447A01, Rev. F
MDS 1710A/C and MDS 2710A/C/D
3
Often, a radio system consists of many widely separated remote radios.
A point-to-multipoint or SCADA (Supervisory Control and Data Acqui-
sition) system may be a new installation for automatic, remote moni-
toring of gas wells, water tank levels, electric power distribution system
control and measurement, etc.
The radio system may replace a network of remote monitors currently
linked to a central location via leased telephone line. At the central
office of such a system, there is usually a large mainframe computer and
some means of switching between individual lines coming from each
remote monitor. In this type of system, there is a modulator/demodulator
(modem) at the main computer, and at each remote site, usually built
into the remote monitor itself. Since the cost of leasing a dedicated-pair
phone line is quite high, radio is often used as an alternative communi-
cation medium.
Invisible place holder
Figure 2. Typical MAS Point-to-Multipoint Network
Point-to-Point System
Where permitted, the transceiver may also be used in a point-to-point
arrangement.
A point-to-point system consists of just two radios—one
serving as a master and the other as a remote—as shown in
Figure 3
. It
provides a simplex or half-duplex communications link for the transfer
of data between two locations.
Figure 3. Typical Point-to-Point Link
RTU
RTU
RTU
RTU
RTU
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
HOSTSYSTEM
MASTER RADIO
REMOTE
MASTER
HOST
COMPUTER
RTU
