Device driver writers have three possible implementation schemes for device drivers supporting PCMCIA cards. They can write a standard protected mode Plug and Play driver, they can rely on standard Windows 95 drivers for certain devices, or they can write a 32-bit protected mode Card Services client. Device driver writers can still add Card Services calls to their Plug and Play drivers, but these drivers will not be bus-independent. The choice depends on several factors, including the completeness of the Card Information Structure (CIS) on the PC card, whether the driver needs memory services, and whether the driver is expected to support the same type of hardware on another bus (that is, whether it is a bus-insensitive driver).
Generally, you should write standard Plug and Play device drivers for your PC Card. For LAN cards, write NDIS 3.x-compliant drivers. For SCSI cards, write miniport drivers. For modems, use the VCOMM driver and include the appropriate AT command strings in the INF file for the Windows 95 Remote Network Access (RNA) software.