PCI Modem VISA in Labview

[chappell77]

I am trying to talk to a PCI modem through a VISA interface.  I have successfully talked to the Modem using Hyperterminal and everything went well but I cannot get Labview or the MAX VISA sessions to talk to the Modem.  I have tried using the VISA Device Driver Wizard to create new .inf files for the Modem, installed them and still nothing.

The modem I am using is a 3COM US robotics PCI Modem (3CP2977).

[Dennis_Knutson]

Why did you use the device wizard to create a new inf file? Normally, a modem will show up in MAX/Device Manager as a new com port and you just have to read/write to that com port. I would revert back to the driver that shipped with the modem. Before you created the new inf file, how exactly did you try to use MAX? Did you get any error messages?

[chappell77]

I tried MAX using Basic I/O write and read.  I wrote the ATA message and read came back with ATA.  After reading the information I could found it lead me to believe that Labview wouldn't operate correctly with the factory driver and I needed the INF to communicate with the modem.

I went back to the factory driver as suggested and MAX still gives the command I sent.  The modem still does nothing.  Should I be getting the OK back from the modem when using Basic I/O read?

[Dennis_Knutson]

You should be getting the OK back. Are you sending a CR character at the end of your command? The only modem program I have access to right now appends this. In MAX, select \r as the character to append and see if that makes a difference. In LabVIEW, if you've got a string control or constant, right click on it and select '\' Code Display in order to enter the actual control code and not the separate characters "\" and "r".

[chappell77]

Guess this goes to show that the simplest things are the easiest to overlook.  It needed the \r to work and I was appending \n.  Thanks for the help Dennis.