IP Relay – 2x relay + RS-232 / Ethernet converter
HW group
June 2006
www.HW-group.com
Page 21 / 28
Parameters of TCP and UDP connection
====== Active (Client/Server) mode ======
S: Send to IP
192.168.0.252
The IP address and the port of the opposite side that will be connected for the data transmission from a
serial port. Setting to 0.0.0.0 will switch the converter into a
passive mode.
U: Port
23
Configuration of the device's communication port – range: 1 .. 19.999.
Note:
If you are using communication via UDP it’s necessary to enter the address of the opposite
side here. The converter does not initiate the connection so the responses are sent to this address!
T: IP mode
TCP
Switches between the TCP and UDP protocols. UDP is faster but packets can be lost or delivered out of
order. Hence it is suitable for communication only on a local network segment in request-reply mode,
usually for converting a RS-485 communication. UDP communication is difficult to debug because no
simple PC terminal, like TELNET terminal for TSP/IP connection, is available.
In TCP it is possible to use the NVT commands and a TEA encryption. Responses of the converter
in case of question/answer protocols in the TCP mode can be slower up to 40% caused by setting
up the connection.
IP mode: 0: TCP / 1: UDP
V: NetworkVirtualTerminal Off
Network Virtual Terminal allows the interpreting of Telnet protocol sequences including certain
RFC2217 extensions, enabling on-the-fly changes of serial port parameters (speed, parity, ...).
NVT description can be found on our website >> „Support & download” >> „
NVT (Network Virtual
Terminal) protocol description
”.
When communicating with the serial port using telnet, e.g. with the TeraTerm program, this option
should be turned on. Otherwise, telnet control commands (seen as "junk") intended for configuration
negotiation at the beginning of the communication are forwarded to the serial port. If you don't want
to use this option, set your client to RAW communication mode.
0: Off
(don't use telnet control code, pass through to serial port)
1: On
(accept telnet control code)
K: Keep connection Off
This option allows keeping the connection alive with sending NOP commands, because TCP
automatically closes the connection after 50 seconds of inactivity. NVT must be enabled for this
parameter to work.
0: no keep connection
(preferred)
1: keep connection
E: Erase buffer on
Open connection
Option to clear the internal Device buffer whenever a connection is established or closed. This
option is useful e.g. if your device periodically says “I'm alive” and you don't want to waste time
retrieving these notifications from the buffer.
0: none
1: Close TCP/IP connection
2: Open TCP/IP connection
3: Open & Close TCP/IP connection