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CHAPTER 40
Free terminal protocol
405.1200.037.2 - Rel.: 2.21 of 25/02/2008
40-2
Our VT terminals can be connected with the majority of devices on the
market, but, given the considerable number and variety of these devices, it
may happen that one is incompatible. To meet the needs of those using an
incompatible device, we have created a special driver called
Free terminal .
Free terminal
protocol
The operator terminal has a type of driver called Free terminal that makes
it possible to communicate with any type of intelligent device not supported
by the standard drivers supplied. This driver requires that the device man-
age the VT terminal in all its functions; this happens by sending control
characters that the VT interprets and then sending characters to be dis-
played. When a is pressed, the VT sends the device the value of that
such that the device recognizes and, if necessary, uses it.
The free terminal protocol also allows you to create a network of up to 31
terminals (01 -> 31); the connection must be made using serial RS485 (see
“Chapter 35 -> Network connection“
).
To transfer the driver to the VT, the terminal must be set up for reception
(see “Setting up for reception” of the various terminals) before proceeding
to transfer (see Software Manual).
Once the transfer has been completed the VT displays the following page
All the examples quoted in this chapter refer to VT50.
This means that the transfer has been effected properly and that the VT is
ready to communicate with the device.
The transfer of the free terminal automatically sets the serial communica-
tion parameters with pre-established values:
VT address -> 00
Speed
-> 9600 Baud
Parity -> N
Data bits -> 8
Stop bits -> 2
The above page remains in vision so long as the device connected does not
command it to be canceled and takes over control. The connecting cable is
the same as that used for the transfer (see
“Chapter 31 -> PC <-> VT con-
nection“
).
VT-50 TERMINAL Vx.xx