A university I know has an old Nortel PBX. The telecom room is absolutely massive. Filled with cabinets, bix panels and stuff. All of that is at least 35 years

A university I know has an old Nortel PBX. The telecom room is absolutely massive. Filled with cabinets, bix panels and stuff. All of that is at least 35 years old and is still in operation to this day, but a transition to VOIP is planned. I have to respect the reliability aspect of those old systems they were built to last a generation.