I'm trying to verify the presence of an external Compact Flash slot on the Sup2T (VS-S2T-10G) as I don’t have one in front of me, and I found the following module installation guide which seems to suggest that it has a PCMCIA slot - See figure 2-8 and under table 2-22 Supervisor Engine 2T Features
"One PCMCIA slot is available. The PCMCIA slots allow a Flash PC card to be installed providing additional flash memory. You can use this flash memory to store and run software images or to serve as an I/O device. An eject button is located on the left side, next to each slot. Pushing in on the button ejects the Flash PC card from the slot. The slot supports 1 GB Flash PC cards."