I would like to see how this would be translated for VB. After some thought, I do believe Irving is right on with the parallel port as a com link via custom script software. The problem with the Serial port is it's structure dependency to 128byte blocks with bps, stop bit syncing etc. That is out of your control as a UART chip protocol. The parallel port will give you single bit control input. What tools you have in VB to capture the stream is where the challenge lies. Can you create code to capture it in 70-80Ms? I think so, but I have heard VB is very top heavy unless it can be EXE'd to machine language.
If you need more refined explanation of the assembler logic, I can document it better or clue you in to the what,where and why I took this route. This is a small portion of the full source code, so nothing is defined as I/O or variables. Hopefully not too confusing... "on the edge of obscure?" , but somewhat self explanatory if you can follow the archaic mnemonics instructions and labels along with the quirks that a small microcontroller needs for low level support in a powerful, but byte/word/page/bank stingy environment.
My secondary plan for this SX48 code was to go with an RS-232 output section for connection with the Emic text to speech unit Parallax distributes. Mitutoyo already has produced a Voiceman that we funded the development on. That unit is rather limited for use with the digimatic code only. The same limitations are on the voice box SPI put out for for our RS232 digital protractors. It only says xxx.xx degrees at the end of a text string. My version was to have several unit of measure options in the same device. Like pounds, ounces, feet, pieces, hours, what ever.
There are several other applications that we could use Blind adaptive voiced hardware already coupled with OEM RS-232 proprietary format output. Often the interface is all that is required to restructure the data to something either the voicing appliance or braille display can understand. In these applications, the devices must be portable and reasonable inexpensive to adapt. The SX48 proto board was a blessing at $10ea.
Too many other project have priority, so this one is collecting dust. Helping folks with similar interests keeps me cobwebs from getting fuzzy comfy!