Reading a whole frame from the serial port

I have posted before about my attempts to use the serial port (http://forums.ni.com/ni/board/message?board.id=170&thread.id=387410).
Anyway, I want to connect an external device through using VISA. It uses a protocol that exchanges frames. My main program is a series of while loops going through the different echanges, it sends one frame, waits for the proper response, sends the frame again etc.
My problem lies in reading the frames. I'd like to read from the serial port until I get an EOF character, then parse the frame, etc. for every cycle of send/check. This doesn't work. I've managed to get one character from the port, thereby confirming that my reading function does actually read. Then I tried to put it into a loop which resulted in it not returning any characters at all.
Attachments:
AssReq.GIF ‏5 KB
GetFrame.vi ‏14 KB
readVISA.vi ‏13 KB

Attachments:
SerialPortControl_2.vi ‏24 KB

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Reading a whole frame from the serial port

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