Moxa Technologies IA5150 - Manual (Page 24)

NPort IA5150/5250 Series User’s Manual Choosing the Proper Operation Mode
4-4
TCP Client Mode
In TCP Client mode, NPort IA5150/5250 can
actively establish a TCP connection to a
pre-defined host computer when serial data
arrives.
After the data has been transferred, NPort
IA5150/5250 can automatically disconnect from
the host computer by using the TCP alive check
time or Inactivity time settings. Refer to Chapter
5 for more details.
As illustrated in the figure, data transmission
proceeds as follows:
1. The NPort IA5150/5250 configured for TCP
Client Mode requests a connection from the
host.
2. Once the connection is established, data can
be transmitted in both directions—from the
host to the NPort IA5150/5250, and from the
NPort IA5150/5250 to the host.
TCP Client Mode
1Request a
connection
2Proceed with
data transmission
TCP Client
RS-232/422/485
1
2
Device
TCP/IP
Ethernet
UDP Mode
Compared to TCP communication, UDP is faster
and more efficient. In UDP mode, you can unicast
or multicast data from the serial device to one or
multiple host computers, and the serial device can
also receive data from one or multiple host
computers, making this mode ideal for message
display applications.
RS-232/422/485
Device
TCP/IP
Ethernet
Directly proceed with
data transmission
(no connection required)
UDP Mode
Pair Connection Mode
Pair Connection Mode employs two NPort IA5150/5250 in tandem, and can be used to remove the
15-meter distance limitation imposed by the RS-232 interface. One NPort IA5150/5250 is
connected from its RS-232 port to the COM port of a PC or other type of computer, such as
hand-held PDAs that have a serial port, and the serial device is connected to the RS-232 port of the
other NPort IA5150/5250. The two NPort IA5150/5250 units are then connected to each other
with a cross-over Ethernet cable, both are connected to the same LAN, or in a more advanced
setup, they communicate with each other over a WAN (i.e., through one or more routers). Pair
Connection Mode transparently transfers both data and modem control signals (although it cannot
transmit the DCD signal) between the two NPorts.