Initiator of the Data Exchange
On this step you select which side of the VSP-to-DS connection will be the first to send the data.
Notice, that asking "who will be the first to send the data?" is not the same as asking "which side will be establishing the data connection to the other side?"* When making your choice imagine that there is no network at all and the serial device is attached to the COM port of the PC directly. Now, which side sends the data first?
There are three choices:
| • | Virtual Serial Port. Select this option if it is the application software that will be sending the first data. This is typical for the kind of serial devices that we, at Tibbo, came to call "slave terminals". Such terminals communicate with the PC software using some sort of command-reply communication protocol and it is the PC software that usually plays the role of a "master": the terminal won't send any data unless the PC sends a command first (and this is the "first data"!). |
| • | Device Server. Select this option if it is the serial device that will be sending the first data. This is typical for the kind of serial devices that we call "scanners" (readers)**. This class of serial devices differs from "slave terminals" in that they send out the data spontaneously, without any prior prompt from the PC software. |
| • | Any side. In some systems the data may first come from any side. For example, there are some "active terminals" out there that can send out the data spontaneously and at the same time respond to the commands from PC. Also choose this option if you are not sure which side of your system sends the data first. |
* Although these two questions are connected- see how the Wizard decides which side open the connection.
** Meaning barcode scanners or magnetic card readers.