Had a very clever bloke years ago at a previous employers who had written an audio conferencing program that allowed you to route the output of meeting rooms to different areas of the company (and also externally). He'd also designed the switch boxes that the software integrated with to allow selection of company sites, ISDN controllers/dialers for the stand alone ISDN cards and everything. It worked fine (we never had a problem with it in many years of happy use) and the old adage if it ain't broke don't fix it came into play here. You basically used the GUI to pick which sites you wanted to route the audio to (or dialed the number) and from and pressed the big go button on screen.
He retired when we were taken over and the new owners took one look at the Heath Robinson esque switch boxes and non web-based software and said we'll find a replacement. There were rumours that the new set up was chosen by the work experience who was tasked to find something as part of his 'experience'.
Were they true? I couldn't possibly comment.
*There were several software packages (and switch) as they couldn't find just one as a replacement. The fact that these didn't do exactly what we wanted them to do and they weren't as reliable is another matter.