My purpose is to use Digicom Modems LCM 16P with cFP-2020. These
modems should implement a point-to-point communication, between an
embedded application running on cFP-2020 and a PC, running LabView
application (for tests).
I have to use 2 wires between the
modems. In this way, I have to perform Hardware flow control in RS232
communication, because, I suppose, the carrier signal should be on
(over the 2 wires) only when device has to transmitt data. I was told
by Digicom to use RTS signal (pin 7 on DB9 connector).
My question is: when I set VISA 232 property, what is the setting's choice? I mean, in flow control I can choose between -none; -RTS/DTS; -XON/XOFF; .....
I build a simple test application in which I use RTS/DTS flow control
type, but using my scope I observed that the carrier is always present
on the transmission line, instead of beung present only during
transmission. In my test app, cFP-2020 sends data, PC receives data,
so no overlapping is possible.
When I set VISA properties for the modem, the carrier signal on modem goes up, and stops when I close (VISA close) the port.
Suggestins wellcomed!!!
graziano PS.: I've posted this question in LV forum too.
