I used to check that my vinyl cutting plotter was still running and on track remotely from home using Timbuktu, a standard video camera with Quadra 630 class machines at both ends to make & transfer Quicktime VidCaps to download and replay on the machine at home. Then I could load the next job when it stopped and re-start the plotter without driving into the shop to do it.

It wasn't really video-conferencing, but it pre-dated the Web-Cam Video-Conferencing era!