MDS 05-3305A01, Rev. B
MDS 4710/9710 I/O Guide
3
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.
Invisible place holder
Figure 3. Typical Point-to-Point Link
Continuously Keyed versus Switched Carrier Operation
The keying behavior of the master station can be used to describe an
MAS system.
Continuously Keyed
operation means the master station transmitter is
always keyed and an RF carrier is always present, even when there is no
data to send. The master station is always simultaneously transmitting
and continuously listening. Different frequencies must be used for
transmit and receive. This is the method used in many MAS systems,
and is shown in Figure 2. This is useful for high-speed polling applica-
tions.
NOTE:
4710/9710 remotes do not support full-duplex operation.
Switched Carrier
operation is a half-duplex mode of operation where
the master station transmitter is keyed to send data and unkeyed to
receive.
Single Frequency (Simplex) Operation
Single frequency operation (also known as simplex) is a special case of
switched carrier operation. Single frequency operation is automatically
selected whenever the transmit and receive frequencies are set to the
same value. Note that data turn-around times are increased when a
single frequency configuration is used.
1.3 Model Number Codes
The radio model number is printed on the end of the radio enclosure, and
provides key information about how the radio was configured when it
was shipped from the factory. See Figure 4 and Figure 5 for an explana-
tion of the model number characters.
REMOTE
MASTER
HOST
COMPUTER
RTU
