| External Memory compatibility |
| Model | Type of the external memory | Maximum capacity |
| RDC-1 | PCMCIA AIMS card | 24MB |
| | PCMCIA SRAM card | 4MB |
| RDC-2 | PCMCIA ATA card | 40MB |
| RDC-2E | PCMCIA ATA card | 40MB |
| RDC-300 | N/A | - |
| RDC-300Z | SmartMedia memory card (3.3V) | 8MB |
| RDC-4300 | SmartMedia memory card (3.3/5V) | 8MB |
| RDC-4200 | SmartMedia memory card (3.3/5V) | 16MB |
| RDC-5000 | SmartMedia memory card (3.3V) | 32MB |
| RDC-5300 | SmartMedia memory card (3.3V) | 64MB |
| RDC-6000 | SmartMedia memory card (3.3V) | 64MB |
| RDC-7 | SmartMedia memory card (3.3V) | 128MB (*1) |
| RDC-i700 | PCMCIA ATA card | 160MB |
| | CF card | 128MB |
| RDC-i500 | CF card | 192MB |
| | MicroDrive | 1GB |
| Caplio RR10 | SD memory card | 128MB |
| Caplio RR1 | SmartMedia memory card (3.3V) | 128MB |
| *1 : Requires firmware update. |
