Handbook of hardware pinouts, cables schemes and connectors layouts

This is a wonderful site http://pinouts.ru

It contains pin-out diagram & pin details of so many connectors,interfaces,cables,hardware modules and many more.

Few examples are here

Buses and Slots pinouts

Apple Macintosh
obsolete computers
Sun

Memory cards/modules

SIMM, DIMM,...

Misc motherboard connectors

IRDA, cooler,...

Videocards connectors

VGA, DVI,...

Computer multimedia pinouts

audio,video...

Power supply connectors

ATX, WTX,...

Network connectors pinouts

UTP, AUI,...

Input peripherals pinouts

keyboard, mouse,...

Serial interfaces pinouts

RS232, RS422,...

Parallel interfaces pinouts

ECP, IEE1284

Harddisk connectors pinouts

ATA, SCSI,...

Various storage connectors

floppy, tape, cd-rom,...