Sony PCV-R558DS - Manual (Page 67)

System Board 53
PCI Slot Connectors
There are a total of three PCI slot connectors (slot #1 to #3). Two PCI slots
connector (#2 and #3) are available. The PCI slots support 32-bit 5V and
Universal (3.3/5V) PCI add-in cards.
B1 B62 B49 B52
A1 A62 A49 A52
Slot 2 (PCI)
Slot 3 (PCI)
Slot 1 (PCI)