NPort 5000 Series User Manual
68
TCP Client Mode
In TCP Client Mode, the NPort can actively establish a TCP
connection with a pre-determined host computer when serial
data arrives. After the data has been transferred, the NPort
can disconnect automatically from the host computer by
using the
TCP alive check time
or
Inactivity time
settings. Refer to
Chapter 5
for detailed configuration
instructions. As illustrated in the figure, data transmission
proceeds as follows:
1.
The NPort 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, and from the NPort to the host.
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.
Pair Connection Mode
Pair Connection Mode employs two NPort units in tandem, and can be used to remove the 15-meter
distance limitation imposed by the RS-232 interface. One NPort is connected from its RS-232/422/485 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-232/422/485 port of the other NPort. The two NPort 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.
Ethernet Modem Mode
Ethernet Modem Mode is only supported by the NPort IA5000/IA5000A, NPort 5000A, NPort
5000AI-M12, and NPort 5100 series.
Ethernet Modem Mode is designed for use with legacy operating systems, such as MS-DOS, that do not
support TCP/IP Ethernet. By connecting one of NPort’s serial ports to the MS-DOS computer’s serial port, it
is possible to use legacy software originally designed to transmit data via modem, but now transmit the
data over the Ethernet.