Lantronix MSS1-T, Reference Manual

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Introduction Terms
1 - 3
Figure 1-2: Example Four-wire Mode Network
It is important to connect the transmitter of the master device to the wire that is connected to the
receive terminals on the slave devices, and connect the receiver of the master device to the wire
that is connected to the transmit terminals on the slave devices. In essence, the master device will
be connected to the slave devices with a
swapped cable.
The MSS transmitter is always driving and the receiver is always enabled, so the MSS is able to
send and receive data simultaneously. The advantages of four-wire mode are double the
throughput of two-wire mode and a guaranteed open path to each slave device’s receiver.
1.2 Terms
In this manual, the following terms are used to describe parts of a network.
Host A computer attached to the network. The term host is generally used to
denote interactive computers, or computers that people can log into.
Node Any intelligent device directly connected to the Ethernet network such as
a host, a printer, or a terminal server. All nodes have their own Ethernet
addresses. The MSS is a node. Devices connected to the MSS are not
nodes.
Master The device that controlls all other devices on an RS-485 network. An RS-
485 network typically has one master device.
Slave Any device on the RS-485 network that is not the master. An RS-485
network can have up to 31 slave devices.
Session A logical connection to a service. A typical session is a terminal connected
to a host through the server.
Local mode The MSS user interface. It is used to issue configuration and session
management commands and to establish connections. When in Local
mode, users will see a
Local> prompt.
TX
RX
RX
TX
TXA
TXB
RXB
RXA
Shield
Shield
TXA
TXB
RXB
RXA
Shield
Shield
Sh
A
A
B
B
TX
RX
Sh
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Sh
A
A
B
B
TX
RX
Sh
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Sh
A
A
B
B
TX
RX
Sh
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MSS
Slave Slave
Slave
Slave
(Master)