Atop Technology SE8502-M12 User Manual - Manual (Page 12)

User manual Version 1.1
SE8502-M12 IP68 Serial Server
Copyright © 2010 Atop Technologies, Inc.
All rights reserved
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2.3. TCP & UDP Protocols
SE8502-M12 can be operated in two most common protocols TCP and UDP.
2.3.1. Transmission Control Protocol (TCP)
TCP provides a connection and a byte oriented data stream with control parameters such as flow control, multiple
ports option, and order delivery notification. Once the connection is established, data can be transmitted in both
directions. TCP guarantees data is transmitted from one node to the other node(s) in orderly. The protocol also
distinguishes the transmitted data for different applications (such as a Web server or an Email server) on the same
computer.
For redundant or dual-network connectivity purposes, SE8502-M12 offers two TCP operation Modes so users
may choose for their specific application, TCP Server Mode and TCP Client Mode.
2.3.2. User Datagram Protocol (UDP)
UDP is a faster datagram delivery protocol. User can configure SE8502-M12 to work in the UDP mode. UDP is
connectionless protocol and can transmit multicast data to/from a serial device to one/multiple host computer. Because
UDP is the connectionless protocol, UDP does not guarantee the reliability and orderly data streams like TCP protocol.
Datagram may arrive out of order or lose without notice. But the advantage of UDP is the speed. UDP is faster and
hence more attractive in time-sensitive applications.
2.4. Connectivity Topology
SE8502-M12 is also equipped with Tunneling and Virtual COM operation modes. It is designed to transmit data
to/from multiple serial devices and from/to multiple TCP/IP devices on Ethernet, so it can enhance the accessibility of
the serial devices immensely. Fig 4. is the example of SE8502-M12 connection topology.
Fig 4. Typical Topology of SE8502-M12 Connection
2.4.1. Virtual COM Mode
The Virtual COM software emulates a serial port with Internet or LAN topology. In the Virtual COM Mode, COM
port data (RS232) is encapsulated to Ethernet data format. By creating a virtual COM port on a PC, the Virtual COM
driver redirects communications from the virtual COM port to the destination IP address (and the designated port
number) by encapsulated COM data into IP data. Fig 5. illustrates a Virtual COM connection diagram.