Overview to different PCI cards and slot types and ways to combine them

Question

Which types of PCI extension boards and PCI slots are available and which combinations of card and slot are possible?

Answer

During the past years, different variants of the PCI bus were defined for desktop and server computers. This variants mainly differ in means of bus width and signal voltage used:

• Bus width
  Will be 32 bit using PCI 2.x/3.0 or 64 Bit using PCI-X.

• Signal voltage
  Will be 3.3 or 5V.

Derived from this parameters, three main PCI bus types are used in common:

• 32 bit PCI with 5V signal voltage
  This is the typical PCI slot found on usual desktop computer mainboards. Clock speed for data transmissions is 33Mhz. Therefore the maximum transmission capacity calculates to 1 gigabit/s.

• 64 bit PCI with 5V signal voltage
  This PCI slot is usually found on dual processor desktop and server mainboards. Clock speed for data transmissions is 33Mhz. Therefore the maximum transmission capacity calculates to 2.1 gigabit/s.

• 64 bit PCI with 3.3V signal voltage
  This PCI slot is found on modern server mainbords. Often you find the term PCI-X in the technical specification. Clock speed for data transmissions varies from 66 Mhz to 533 Mhz. Therefore the maximum transmission capacity calculates to 4.3 gigabyte/s using 533 Mhz clock speed. The slots maximum clock speed will be shown a number after PCI-X. An example is PCI-X 133.

The above mentioned PCI bus types may be mixed on a single mainboard, because chipsets, especially these types for server appliance, support different PCI bus types at the same time.

The following pictures will allow you to identify the different PCI bus types as of the used socket type. The top of each picture represents the backside of the mainboard, e.g. the slot bracket will be placed there if PCI extension card is plugged into the slot. Please note the coding nose near the backside which will identify a 3.3V only slot and prevent a 5V only card from being inserted because this might damage board or card.

PCI Slot 32Bit / 33Mhz with 5V signal voltage

PCI Slot 64Bit / 33Mhz with 5V signal voltage

PCI Slot 64Bit / 66Mhz with 3,3V signal voltage

On the market you will find various PCI extension cards using different bus width and signaling voltages. But it is possible to identify the correct card type using the coding marks present at the golden socket area of each card. The following pictures show the different card types and matching PCI slots to use the card with.

Overview of the schematic pictures for the different PCI slot types

PCI slot 32 bit with 5V signal voltage

PCI slot 64 bit with 3.3V signal voltage

PCI slot 64 bit with 5V signal voltage

Please note the * in the the follow up pictures. In these cases a PCI cards designed for usage in 32bit/33Mhz Environments is used in a 64bit PCI slot. If the slot is designed to run with 66Mhz bus clock or higher, the cards will limit ALL cards connected to the bus down to 33Mhz. This may affect the peak transmission rate of fast RAID or gigabit/ATM network controller cards!

• PCI card with 32 bit and 5V signal voltage
  The formerly sold PRI-card HST SAPHIR V Primary PCI matched this type. Therefore this cards couldn't be used in 3.3V only slots!

PCI extension board 32 bit with 5V signal voltage and matching PCI slots

• PCI card with 32 bit using 3.3V or 5V signal voltage
  The currently sold cards SX2 QuadBRI , SX2 SinglePRI , SX2 DualPRI and the formerly sold cards Digi DataFire Micro V , Digi DataFire Quad Micro , HST SPAHIR V-B  are matching this this type. Therefore these cards can be used in 3.3V and 5V slots!

PCI extension board 32 bit with 3.3 and 5V signal voltage and matching PCI slots

• PCI card with 32 bit and 3.3V signal voltage
  This type of PCI cards is very rare and could only be used in 64bit slots with 3.3 signal voltage or with new 32bit PCI slots compliant to PCI v2.3.

PCI extension board 32 bit with 3.3V signal voltage and matching PCI slot

• PCI card with 64 bit and 5V signal voltage

PCI extension board 64 bit with 5V signal voltage and matching PCI slot

• PCI card with 64 bit using 3.3V or 5V signal voltage

PCI extension board 64 bit with 3.3 and 5V signal voltage and matching PCI slots

PCI card with 64 bit and 3.3V signal voltage

PCI extension board 64 bit with 3.3 and 5V signal voltage and matching PCI slots

Physical board format:
Beside the many aspects already mentioned, another aspect is the physical size/format of the boards.

Full-height - therefore does not fit into a low profile slot
Half-length - fits also into a full-length slot

In general also the opposite does apply:
Board with half-height do not fit into a slot with full-height (except you shorten or exchange the slot bracket coming with the board).
Board with full-length do not fit into a slot with half-length.

All SX2 and SX2-Express ISDN boards currently offered by Swyx are made in the following format:
Full-height, Half-length
Swyx does not offer ISDN board in half-height or full-length at the moment.

PCI-Express: Since summer 2004 a successor of the well known PCI standard is available: PCI-Express. This standard is electrical and logical not backward compatible with PCI / PCI-X.

You can find further general information about PCI-Express here.

Since 2008 Swyx offers all ISDN board also in a PCI-Express layout, beside the classic PCI based boards:
The model name of all PCI boards starts always with "SX2", followed by QuadBRI, SinglePRI, or DualPRI.
The model name of all PCI-Express boards starts always with "SX2-express", followed by QuadBRI, SinglePRI, or DualPRI.

So you just have to take care to order the correct Modell which is compatible with the type of slots used in the server hardware.
Mixing of PCI and PCI-Express boards within the same computer is not possible!

All recent Swyx SX2-Express ISDN boards are PCIe-x1 boards and therefore work also x4, x8 und x16 slots.