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245U-E Wireless Ethernet Modem User Manual
Rev Version 2.24
The serial gateway can be configured as either as server, client, multicast group, or Modbus.
• Server—When configured as server, the module will wait for a TCP connection to be initiated by a
remote client.
• Client—When configured as client, the module will automatically attempt to connect to a specified
remote server using TCP.
• Multicast Group—When configured as multicast group, the module will broadcast data to all members
of the same multicast group using UDP.
With the serial gateway server, client, and multicast functions it is possible for serial data from a 245U-E to
be transferred to any other 245U-E serial ports including the corresponding port on the same 245U-E.
Serial Gateway (Modbus RTU to TCP)
When configured as Modbus, the module will allow a serial Modbus client (master) to connect with a single
Ethernet Modbus TCP server (slave). With the Modbus function, the serial data is encapsulated within a
TCP/IP data frame and made available on the Ethernet network. Both 245U-E serial ports and the hard
wired Ethernet port can be configured to communicate completely separate data streams that can all be
communicating at the same time.
Some of the possible serial gateway topologies are shown in Figure 40.
Figure 40 Serial Gateway
There are software packages available (such as SerialIP Redirector by Tactical Software) that can create
a virtual serial port on a PC. This virtual serial port can be configured to connect to a 245U-E serial port.
Standard programs can then be used to access this serial port as if it were actually connected to the PC.
Alternatively, HyperTerminal may be used to connect to a serial port on the 245U-E. When creating the
HyperTerminal connection, select “Connect Using: TCP IP (Winsock),” enter the IP address of the 245U-E
and the port selected in the “Network port” field.
