I regularly participate in Zoom, Webex and doxy.me web meetings with audio and video.

If all you want is an audio conference call, my telephone provider can do that. No computer programming or even computer required!

At one time, I had a Win XP laptop that just couldn't run Skype.

If your current machine is not capable of having a Zoom meeting, then I would just forget it.

We could get into details about how much bandwidth and latency requirements there are for this stuff. But I believe that is pointless.

If your machine cannot run a commercial conferencing app, the probability that you can re-create the functionality of said commercial app, is close to zero.

If all you want is a telephone conference call, use your telephone.