CompactPCI Serial (PICMG CompactPCI-S.0), originally known as "CompactPCI Plus", is the successor to CompactPCI. This independent specification is built on entirely serial architecture and offers a data transfer speed of up to 32 Gb/s. However, a soft migration path from parallel to serial architecture is possible. For this purpose PICMG has created an additional sub-specification, PICMG 2.30, to CompactPCI (PICMG 2.0), which is also known as CompactPCI PlusIO. This route saves customers time and money.

Schroff has developed systems and backplanes for this specification. An example is an 8-slot hybrid backplane with three CompactPCI peripheral slots, one CompactPCI PlusIO system slot and four CompactPCI Serial peripheral slots. This backplane has three rear I/O slots in the CompactPCI bus area. This represents the maximum configuration for hybrid systems and can therefore be used for the most diverse of applications. Backplanes with fewer slots, e.g. 5, are being developed.

For CompactPCI Serial Schroff initially also developed a system in maximum configuration with 9 slots - one system slot (left) and eight peripheral slots. Here again the widest variety of applications are possible. Four different backplane versions (single-star with/without rear I/O and full-mesh with/without rear I/O) are defined, such that PCIe, USB and S-ATA (serial ATA enables direct connection of hard disks to the backplane) are realised as single-star. The backplane versions differ only in terms of Gigabit Ethernet. One version provides this as single-star and the other as full-mesh. The latter arrangement is suited to e.g. processor farms or clusters.

The mechanical construction of the hybrid system and of the CompactPCI Serial system matches the Schroff 8-slot CompactPCI 3+1 system with built-in 1 U fan drawer. Two PSU types are available for the power supply, according to customer preference. The 19" PSU (3 U, 8 HP, 160 HP) with an output capacity of 250 W and rear IEC mains input socket makes even the tolerances set out by the specification for limiting values of currents, voltages etc, still smaller. This is of particular benefit where multicore processors are present. This PSU is also available in a 48 V version for custom applications. A low-cost alternative is the option of an ATX PSU.

Optimal cooling of the system is assured by a hot-swap fan drawer under the board cage that pulls out to the front. This can optionally be upgraded with a filter mat. Depending on the PSU selected, the drawer is fitted with either two or three fans that can be quickly replaced when necessary.