User’s Manual
Appendix 3
Key Parameters of ESERV-10
Parameter Available
Scale
Default Description
Serial Speed
1200…38400 bps
9600
Serial port speed
Data Bits
7 or 8
8
Number of data bits in serial port
Parity Method
None, Even, Odd
None
Serial port parity:
None = no parity
Even = even parity
Odd = odd parity
Stop Bits
1 or 2
1
Number of stop bits in serial port
Flow Control
None, HW, SW
HW
Serial port flow control
None = no flow control
HW = CTS/RTS hardware flow control
SW = software flow control
Send Timeout
0 … 5 s
Time that ESERV-10 waits between receiving
last byte from serial port and transmitting it to
the Ethernet
Communication
Mode
UDP or TCP
Protocol that enables connection from the
Internet to the serial port
Inactivity Timeout
TCP Hangout
30 s … 16 h
Time that ESERV-10 waits between receiving
last packet from the Ethernet and closing the
connection (TCP).
Serial Speed
– ESERV-10 and the attached serial device must agree on a baud rate word for serial
connector. Valid baud rates are 1200, 2400, 4800, 9600, 19200 and 38400 bits per second.
Data Bits, Parity Method, Stop Bits
– define the details of the interface mode between the serial
device and ESERV-10.
Flow Control
– Control of the data rate at which hosts or routers inject packets into a network or
internet, usually to avoid congestion. In serial data transmission flow control is not necessary from
the ESERV-10’s point of view if packets received through serial port are less than 512 bytes and
data flow isn’t continuous. If the amount of data is large, flow control should be used.
Send Timeout
– This parameter specifies the length of the time period that ESERV-10 stores the
data from serial port before it sends it further to Ethernet. A short time period is advantageous if the
data in serial transmission is packet-formed (the whole packet is transmitted as consecutive bytes).
A longer time period is preferred if the serial device transmits data gradually.
Connection Mode
– This parameter specifies the protocol used to make a connection to ESERV-
10’s serial port via a configurable UDP/TCP port.
Only one of these two protocols can be used.
Inactivity Timeout
– This parameter enables closing of the connection after a period if the
connection between the PC and ESERV-10 is lost or unexpectedly closed. Small Inactivity timeout
value is suitable for short time period connections, for example, when parameters are randomly
inquired from a device connected to ESERV-10’s serial port. A large value is suitable if connection
is sustained between ESERV-10’s serial port and target device (PC) and data is transmitted
continuously. For example, in the Windows OS the default value of Inactivity Timeout is 1.5 hours.
Note:
When a TCP connection exists between the ESERV-10’s serial port and the target device,
no other connection can be established from any other device. If data transmission is
simultaneous and several connections are preferred, UDP must be considered as a
reasonable alternative.
Note:
ESERV-10 offers the possibility to interrupt the existing TCP connection by sending a
”RST” character string to its control port (UDP port 8001). This can be utilized if it is
absolutely necessary that one party establishes a TCP connection to a serial port.
ESERV-10
30
Viola Systems Ltd.
