I am trying to find some statistics on average time to repair or troubleshoot VoIP and TDM PBX. We heard PBX takes 30 minutes versus VoIP at 4.5 hours -- is this true?
No, absolutely not. It depends, of course, on the problem and other details of the issue. But, since VoIP provides you the option of moving to another switch port, it may actually be lower. Another thing to also consider is whether or not the expertise to fix the problem is in-house.
VoIP is very easy for network managers to troubleshoot and correct -- baring some unforseen outage -- as most of the gear is very hearty. You could simply move them to another switch port. Depending on your configuration and how much knowledge transfer you gain at the time of install, I would venture to say that the necessary time to troubleshoot a VoIP system or a TDM PBX could be very similar.
That said, if there is a problem with your TDM PBX -- a large portion of the repair depends on parts availability. As things move more towards VoIP, some vendors have stopped development, or are about to, for the legacy PBX equipment -- though all of this will vary from manufacturer to manufacturer. They will all be able to provide you with their statistics. And like I said -- don't forget to check the labor pool locally. Local support is key whether in-house or close-by.