Replacing the PCA66 Series of Network Interface Modules (NIMs)

The PCA66 Series of NIMs has no drop-in replacement.  This series used the COM90C66 ARCNET controller chip that is no longer available.  Second-hand PCA66 NIMs might be obtained from vendors of used ARCNET equipment, but Contemporary Controls does not know of any such vendors.

For users willing and able to modify their application-layer software, currently available NIMs could possibly substitute.  PCX20 NIMs fit in ISA slots and use the COM20020 ARCNET controller chip.  PCI20U NIMs fit in PCI slots and use the COM20022 ARCNET controller chip.  Due to the differences between the COM90C66 chip and the COM20020/22 chips, ARCNET functionality will change.  If you are thinking of replacing a PCA66 NIM with a NIM that uses the COM20020/22 chip, note the following important considerations:

• Memory mapping can no longer be used for data operations because a COM20020/22 chip transfers data through its I/O space.
• 16-bit data operations are not supported by our drivers, but 16-bit operation is possible for those writing their own drivers.
• Although PCX20 and PCI20 software drivers are available, they alone will not provide an upgrade.  A software rewrite will still be required.
• Contemporary Controls does not rewrite software for users.

PCX20 NIMs have free null-stack drivers available for Windows NT/95/98/ME/2000/XP — use of NDIS drivers is strongly discouraged.  Each downloadable driver file is actually a set of files which includes a programmer guide and sample applications.  PCX20 drivers, more driver information and utilities are available at:

• www.arccontrol.com/pcx20_software.htm

PCI20U NIMs have free null-stack drivers available for Windows NT/95/98/ME/2000/XP/Vista — use of NDIS drivers is strongly discouraged.  Each downloadable driver file is actually a set of files which includes a programmer guide and sample applications.  PCI20U drivers, more driver information and utilities are available at:

• www.arccontrol.com/pci20_software.htm

PCX20 and PCI20U NIMs provide most of the same transceiver options as PCA66 NIMs except that the twisted-pair star option is no longer supported and fiber ports are no longer supported.  If you need to replace a PCA66-CXS, you should use a 93-ohm terminator attached to a Tee on the BNC connector of the replacement NIM.  If you need fiber connectivity for a PCX20 or PCI20U NIM, you should use an AI Series hub for the media conversion.