QUATECH's single port SSCLP-200/300 and dual port DSCLP-200/300 universal PCI serial cards, available from Interworld Electronics , provide support for RS422/485 full duplex and RS485 half duplex operation with auto-toggle RS485 driver control and are compatible with 5V and 3.3V PCI and PCI-X slots.
The PCI bus has gone through a number of generational changes. It started out as a 32-bit bus operating at 33MHz with a 5V supply. The original 32-bit architecture was upgraded to 64-bit at 66MHz or 32-bit at 33MHz with a 3.3V supply. The new PCI-X architecture provides a 64-bit bus at 133MHz with a 3.3V supply.
Most PCI serial add-in cards are designed to operate in the original 33MHz 5V bus. Quatech's universal PCI cards will work in both 5V and 3.3V buses including the PCI-X bus. Note that installing a SSCLP-200/300 or DSCLP-200/300 in a PCI-X slot will force the PCI-X bus to operate at 33MHz.
This may not be a problem as most computers have more than one PCI-X bus and any true PCI-X cards can be installed in a separate bus. At this point in time there are no 64-bit 133MHz serial cards for the PCI-X bus and using a Quatech Universal PCI card may be your only option. Quatech's Universal PCI cards support baud rates up to 460.8kbps, share a single PCI interrupt and provide Windows 95/98/Me/NT/2000/XP and OS/2 driver support.
Quatech's universal PCI cards also have a low profile form factor making them ideal for installation in 2U rack mount industrial chassis.