Welcome to Part 6 - this is the penultimate instalment...
8. Legacy hardware – modem cards, fax boards
Basically there is simple advise here, make sure you identify attached hardware on the servers you intend to consolidate (or virtualise) during the audit phase. Lots of hardware either won't virtualise or can't be assigned to specific applications so co-hosting might not be possible. In addition it has been common to have remote management of the servers performed by an attached modem (PCI or otherwise) - this may cause you a security or technical issue if you intended to consolidate.
You should also pay attention and try and spot all those other attached devices such as tape units while you are at it! Consolidation is a good enabler for centralised backups or at a minimum a checkpoint in your regime.