Pass Keystrokes To Another Program

Is it possible to write a VBA macro that passes keystrokes to another program? I have a spreadsheet with over 650 UPC codes for new products that have to be entered into our inventory system. I have downloaded and tried a few macro recorders that record keystrokes and mouse movements, but find them to be unreliable at best.

When I use the macro recorder to automate a task in Excel, (such as moving data from one sheet to another or importing data from a text file) I always go in after I'm done recording and add additional code to bullet-proof the macro (make sure the focus is set properly, etc.). I need to have this kind of control for this task and a macro recorder doesn't give me that (at least not these lower-end shareware programs I have been trying). I know that there are some higher-end macro recorders that include scripting that you can write and edit, but this our "slow" season business-wise and my supervisor has made it clear that he doesn't want to spend any money right now.

My task is simple (just very repetitive, which is why I don't want to spend all day sitting in front of my PC doing this):
1. Open Excel spreadsheet, go to starting data cell
2. Open 3rd party application and go to the appropriate data entry screen
3. Write a macro that does the following:
- checks to make sure the sheet is the active sheet
- copies contents of the active cell
- moves focus to other app and pastes data from active cell
- moves focus back to spreadsheet, copies the contents of the cell to the right (using ActiveCell.Offset?)
- makes other app active and pastes data
- repeat copy/paste for the next cell to right (in spreadsheet)
- press twice to save record before returning focus to the spreadsheet
- move cursor down one line, repeat entire process until active cell is blank

Is this possible to do? The third party program is not able to listed as a reference in VBA, but I didn't know if it was possible to at least pass keystrokes to it. It is actually a terminal emulator (Anzio Lite). I guess the full-blown version of the program has some scripting capabilities (from the documentation I've read), but the Lite version does not.