Intel ISA Bus Specification and Application Notes -

Atari PC1 ISA expansion adapter isa slot pinout Try to ensure that the wiring at the connector that gets into the ISA slot is checked every part of the device(every IC,all those jumper wires isa expansion slot Table 4 11: PCI Connector Pinout 5V System Environment slot is located such that dedicated ISA, EISA, or MC slots are

isa slot function ISA is Industry Standard Architecture, and was provided in the PC motherboard, so it is pretty old, 16 bit and the EISA with deeper 32 bit