Why and in what sense are the din 4164 standard connectors

Question

Question: 1. What are the three components or elements necessary to define a computer bus?

2. Why, and in what sense, are the DIN 4164 standard connectors specified by the VMEbus standard better than the connectors used by the IBM PC bus?

3. A bus driver has the following characteristics:

I_OL      25 mA

I_OH    -15 mA

This driver drives a bus whose receivers have the following characteristics:

I_{IL         -0.1 mA}

I_{IH           10 μA}