The "12123" likely refers to , an older release of the software. While this version is frequently sought for use with older "hex-usb+can" cables (often clones), it is no longer the "best" or most secure version available.
Searching for "vcds pci 12123 download" typically refers to the software used for Volkswagen Group vehicles , specifically distributed by PCI Diagnosetechnik (a major German distributor). Software & Download Information vcds pci 12123 download best