An example of:
Collecting Data Remotely From a Working Printer:
System Characteristics:

Printer has parallel interface.
Logging is generic text , but may also include print emulations such as Laser Printer PCL, Epson, Okidata, and others. "GDI" Win Raster Parallel Printer Interfaces are not useable. Printer can keep working while logging occurs. Print source is from PC, POS, or analytical instrument equipment. A log PC runs "free" Tera Term terminal emulation software in LOG Mode. Print data is constantly logged to a PC folder, 24 hours/day. Log data file may be remotely accessed when convenient by the user.

Basic tests with Tera Term software show that the print data is logged accurately even if the log file is opened and read during active logging. This could mean that the users choice of remote access software for retrieving the log file will not affect the logging function during the retrieval. It may be possible to eliminate the Log PC by running the Tera Term software inside the Source PC and use its COM Port. After the data is landed in a folder at a remote capture site, the user may apply resources to display, archive, parse or even print the data.

Here is a YouTube video that helps show the Tera Term log file being read by Notepad without affecting active recording of the print data to the Tera Term log file: Capture to Tera Term while accessing it's log file at the same time. 3:49 minutes