This page is a part of VPortPro online Help Manual.
VPortPro-client with Com Port Control by Labtam.
VPortPro makes serial (RS232) data from your PC available on TCP/IP-based networks and makes TCP/IP data available on virtual serial ports of your PC. Visit Home of VPortPro for more information.

Adding a Connection Channel

When you click the Add button in the VCOM-TCP Primary Client window the Adding a Connection dialog brings up:

This dialog allows you to specify a connection channel that you want to add to the connection channel list. A connection channel is made up of a serial port number, its initial settings, a TCP/IP address and TCP/IP port number of a serial server, and a transport data stream protocol type.

To add a new connection channel:

  1. In the Serial port list box, select a free serial port
  2. Make Initial settings for the serial port parameters
  3. Specify a TCP/IP address of a server
  4. Specify a TCP/IP port number of the server
  5. In the Protocol Type box, choose a transport data stream protocol type
  6. Press OK

Your settings become effective just when you click the OK button.

In the Serial Port list box, you can select from the available virtual ports list a serial port for the connection channel you want to add. Then you can use the Initial settings button to specify the configuration parameters for the current COM-port to their default or desired values. Serial ports that already exist in the MS Windows (such as COM1 for a local serial port) are automatically excluded from the available virtual ports list to prevent conflicts.

In the TCP/IP Server box, you must fill in the TCP/IP address and TCP/IP port number of a serial server that you want to connect to for the connection channel.

You can specify any port number between 1 and 65535 which does not cause conflicts between services and VCOM-TCP Primary Client. To prevent conflicts between services and VCOM-TCP Primary Client, it is recommended to use free port numbers between 1024 and 65535, i.e. unprivileged ports and not used by services. (See also the services system file.) A PC application employs ports on a serial server when it uses the COM ports that are created and managed by the VCOM-TCP Primary Client.

The Protocol Type

In the Protocol Type box, you must choose a transport data stream protocol type that the VCOM-TCP Primary Client will use in that connection with the serial server. For connection protocol, the setting must match the TCP/IP protocol that the serial server supports.

Most MS Windows applications perform only the common read/write operations that all serial servers support. Some applications, however, also require some of the features provided by the COM Port Control protocol specified by IETF RFC 2217. For these applications, the serial server must support the COM Port Control protocol and provide at least the serial port control and status functions that the application requires.

There are two options for the transport data stream between the VCOM-TCP Primary Client and the serial server:

Raw TCP connection

Raw TCP connection is used to communicate with a serial server without any additional protocol. Although this is possible with most servers, it is not recommended because it precludes the use of helpful Telnet (RFC 2217) protocol features.

Telnet (RFC 2217)

Telnet is the correct setting for most serial servers. If this protocol is selected, the VCOM-TCP Primary Client will automatically request the use of the Telnet "binary mode" to allow proper operation of applications. If the serial server supports the COM Port Control protocol (RFC 2217), it will automatically be used.

General TCP/IP settings are described in section Using ComSetup of chapter Configuring VPortPro. For more information, refer to Appendix A. TCP/IP Connection Overview.

Reconnection Settings

With the Enable reconnection check box enabled, the VCOM-TCP Primary Client will initiate periodical attempts to reconnect the TCP/IP client connection that gets closed. If the connection fails, the connection attempt will be repeated for a user-defined number of times and interval. If the connection attempt fails beyond the user-defined limit, then a pop-up message will appear informing the user that the TCP/IP port is not available and ask if the user wants to keep retrying (the message can be disabled if desired).

This option is useful when any disruption in connection will cause the VCOM-TCP Primary Client to automatically go to stop. If the option is disabled, the VCOM-TCP Primary Client does not restart.

The Reconnection period setting specifies the frequency of these attempts (in seconds). The default value is 10.

The Number of retries setting specifies the maximal number of these attempts. The default value is 10. The maximal value is 1.000.000. You can enter value 0 for a very large number.

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