The PC Card Drive HPC-301 is still the only way to read and write Atari Portfolio memory (Bee) cards on a PC. Make that an old PC with an ISA slot for the interface card and DOS. The driver can be found here and here. In the PofoWiki (German), there’s more information about its usage and what needs to be considered when you have Windows 9x. For me, the DOS mode worked fine and I had less trouble accessing the card reader after loading the driver without parameters, e.g. DEVICE=C:\CD.SYS.
There seems to be another way to access the card drive: A software called Portfolio RAM-Card Reader by Digital Data Deicke (now Pentagon GmbH) is mentioned in the Atari-Home.DE forums here and here. It is reported to work even under Windows XP via Direct I/O.
Today, we’re only going to have a look at the hardware. Just look at this massive cable with 37-pin D-sub connectors that connects the card drive with the interface card:
