Continuously-Keyed Versus Switched-Carrier Operation; Single-Frequency (Simplex) Operation; Installation Planning; Typical Installation - GE DS-SD4-1 Reference Manual

Table of Contents

Continuously-Keyed versus Switched-Carrier Operation

The keying behavior of the master station can be used to describe the

operation of 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 transmitting and receiving

simultaneously. Different frequencies must be used for transmit and

receive. This is the method used in many MAS systems, as is shown in

Figure 4. This network arrangement is useful for high-speed polling

applications.

NOTE: The SDx acting as a master does not support full-duplex oper-

ation.

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 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: Data turn-around times are increased when inter-working with

an MDS x710 network. This restriction does not apply to

homogeneous SD networks.

Careful planning of the installation site helps achieve optimal performance

from the transceiver. This section discusses pre-installation factors. After

reviewing this section, refer to the step-by-step installation procedures begin-

ning on Page 18.

Figure 6 shows a typical station arrangement. Wiring connections and installa-

tion steps for the transceiver are provided in the sections that follow.

SD Series Reference Manual (x710 Mode)

MDS 05-4670A01, Rev. E

Table of Contents

Mds sd series