IP Relay – 2x relay + RS-232 / Ethernet converter
HW group
June 2006
www.HW-group.com
Page 26 / 28
Application hints
Security
For raising the security of data transfer in TCP mode it’s possible to authorize both sides on
establishing any TCP/IP connection via TEA 128 algorithm with symmetric signature. The
configured password of both sides then won’t go throughout the network. This option is possible
only for TCP/IP connection. UDP mode is designed only for local networks. Detailed description of
TEA can be found in the handbook “
Programming of Ethernet Applications
”
on our website.
Extension of the timeout connection
Since the converter supports only one connection at the moment it’s necessary to secure the
timeout for this connection. Standard limit after which the connection is terminated in case of no
data flow is 50s. With regard to the routine it’s possible to enable option „
K: Keep connection
“,
which in 10-second intervals sends the NOP command into the open NVT connection.
Network Virtual Terminal
Learn how to use Network Virtual Terminal in your application. Basically the NVT is a system on which
TELNET protocol works. It’s simple and transparent way of handing down the setup information which is
compatible with all sorts of RFC and above all with
RFC2217
for remote control of serial port.
Free application software
Use supplied free software for configuration or inspiration for creating drivers. Detailed description
or routines, TEA encoding and our NVT implementation can be found on our web.
•
Borland C++
– example of
communication over TCP/IP a NVT
(TCP Client).
•
Borland C++
– TCP server solution
example.
•
Delphi
– example of communication
over TCP/IP a NVT (TCP Client).
•
JAVA
– example of communication via
TCP/IP – NVT (TCP Client).
•
PHP
– example of device
communication over TCP/IP – NVT
(TCP Client).
•
Visual Basic
– example of device communication over TCP/IP a NVT (TCP Client).
