MDS 4710B, Инструкция по установке и эксплуатации

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MDS 05-3316A01, Rev. E MDS 4710B/9710B I/O Guide 3
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. Continuously keyed operation is inherently full duplex.
The master station is always simultaneously transmitting and continu-
ously listening. Different frequencies must be used for transmit and
receive. This is the method used in most MAS systems and is shown in
Figure 2.
Switched Carrier operation is a half-duplex mode of operation where
the master station transmitter is keyed to send data and unkeyed to
receive.
For proper operation, x710B radios must be specifically configured to
listen to either a continuously keyed or switched carrier master. The
SWC
command is used to select whether or not a radio is listening to a
switched carrier master. The default setting is
SWC OFF
, for communica-
tions with a continuously keyed master.
MDS x710B radios always transmit using switched carrier operation. If
a radio system is configured with an x710B as the master, all radios
(master and remotes) must be configured with
SWC ON
. This situation is
shown in a point-to-point system in Figure 3.
Single Frequency (Simplex) Operation
Single frequency operation (also known as simplex) is a special case of
switched carrier operation. The
SWC
command must be set to
ON
. 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.
1.2 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 for an explanation of the
model number characters.