Issue
What are termination resistors used for?
Environment
I/NET Site
Cause
What are termination resistors used for?
Resolution
As the signal travels down the cable, it sees a characteristic impedance (AC resistance). The closer it gets to the end of the wire, the higher the impedance goes until it gets to the end where it reaches infinity. Ohms law..so the voltage signal goes up and causes a reflected signal back up the wire at a lower energy level. This can be seen by the controllers as noise and if the timing is right, can disrupt communication. The timing and reflected signal level are functions of the cable length. Using termination resistor presents the signal with a consistent impedance and clamps the reflection. (They're also referred to as clamping resistors.)