To my knowledge all modern DCs have out-of-band networks for this sort of thing that provide serial access to the BMC chip, nothing old school about that. Old school is having to submit a ticket to Jerry in the DC to walk the crash cart down to box 55AE, hook up a serial console, run diagnostics, and attach the output back to the ticket. You only have to deal with Jerry occasionally now, usually when the BMC or power rails fail.