Patent ID: 7030644

Claim:
A simultaneous bi-directional data bus comprising: a simultaneous bi-directional data bus having a characteristic impedance Z 0 ; a first driver unit and receiver unit connected to a first terminal end of the simultaneous bi-directional data bus; a second driver unit and receiver unit connected to a second terminal end of the simultaneous bi-directional data bus; each of the first driver unit and the second driver unit having a sourcing current source and a first resistor connected in parallel between a voltage supply and a terminal end of the simultaneous bi-directional data bus, and a sinking current source and a second resistor connected in parallel between a ground and a terminal end of the simultaneous bi-directional data bus, wherein a substantially higher impedance of each current source relative to a substantially lower impedance of each resistor connected in parallel to the current source provides a relatively constant impedance in each driver unit which substantially matches the characteristic impedance of the simultaneous bi-directional data bus.