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| Properties | Values |
|---|---|
| Serial Port | From the dropdown list, select the serial port which should be used for connection to this Terminal Client TCP network port. Select the Serial Port from among standard serial ports (COMx) or one instance of a pair of Virtual Port pair (VirCOM xxa or xxb) if connecting this Terminal Client port to another process using Virtual Serial Ports. Make sure the Async port is defined under Networks. |
| Serial Buff Size | Maximum number of bytes which will be put into an IP packet to be sent to the network server. Once receiving this quantity of bytes on the serial port, a TCP packet will be sent immediately. The actual amount of data bytes may be less than the Serial Buff Size, if the Demark Timer (below) times out before the Serial Buffer is full. |
| Demark Timer | Maximum time (in milliseconds) to wait before creating and sending a packet regardless of how many data bytes were received on the serial port. This indicates the assumed "demarcation" time between serial packets. If a serial device is periodically sending messages at a defined interval, setting this Demark Timer too high could cause multiple serial packets to be clumped together in one TCP packet, which may not be desirable. Setting this value too low might cause half of a packet to be sent prematurely if there is a momentary glitch or pause in the serial data stream. |
| Client Reconnect Delay | Enter the time (in seconds) that the Terminal Client will wait after a failure to connect, before attempting to reestablish connection with the Server. This only applies when the connection is unable to be established. If the connection is made and then lost, reconnection will be attempted immediately. |
| Ok AT Commands | Select whether to echo an "OK" to AT commands entered at the Terminal Client serial port. The OK is similar to communicating with a modem over its serial port. |
| DTR Indicates Online | Select whether DTR indicates IP connection state. If set to 'Yes', the serial port's DTR signal will be asserted to a positive voltage when the IP connection is established with a remote server, and will be de-asserted when the IP connection is lost. This emulates the Data Terminal Ready functionality of a dial-up modem, giving a physical indication that an active connection is present. |
| Mode Flag | Select the connection mode of the Terminal Server. Always – Select this option to connect automatically upon system restart or upon the IP socket connection being terminated. If using the "Always" mode of connection, there must be only one child Host Connection object with its Dial String set to an empty field. The Terminal Client will use the IP address of that Host Connection object to automatically connect to the end device. Any Data – Select this option to connect the Terminal Client to the remote server only when data is received on the serial port. If using the "Any Data" mode of connection, there must be only one child Host Connection object with its Dial String set to an empty field. The Terminal Client will use the IP address of that Host Connection object to connect when data is received on the serial port. ATDT – Select this option to connect the Terminal Client only if an "ATDT###" message is received on the serial port, where ### is some alphanumeric string. When using the “ATDT” option, there may be many child Host Connection objects defined under this Terminal Client object. The Host Connection entries should have their Dial String configurations set to unique ATDT### values. The “ATDT” option causes the Terminal Client to act as a modem emulator. The connected serial device acts as if it were connecting using a dial-up modem, where each ATDT dial sequence tells the Terminal Client to connect to a destination IP server, rather than dialing over a PSTN telephone network. DCD – Select this option to connect the Terminal Client only when the DCD signal on the RS-232 serial port is raised to a positive voltage. This option allows a physical voltage input on the serial port to trigger the network socket connection. If using the “DCD” mode of connection, there should be only one child Host Connection object with its Dial String set to an empty field. The Terminal Client will use the IP address of that Host Connection object to connect when the DCD control signal is received. ATDT or DCD – Select this option to connect the Terminal Client in one of two modes described above (the “ATDT” or “DCD” modes). When choosing this option, it is required that one or more Host Connection objects be defined with a configured Dial String, and there should also be only one Host Connection object defined with its Dial String set to an empty field. Ifan “ATDT###” message is received on the serial port, the matching Host Connection object is used, and the Terminal Client connects to that IP address. If an active DCD signal is present, the Terminal Client connects to the IP address defined in the first Host Connection object containing an empty Dial String field. |
| Time to Live | Number of seconds to close socket after inactivity (0 disables TTL) After 2019, serial buffer is flushed upon TCP connect if TTL > 5. |
Host Connection
The Host Connection objects are used in conjunction with the Terminal Client to configure one or more IP addresses to which the Terminal Client will connect, and to allow the Terminal Client to be used as a modem emulator.
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