SCSI-1, the original SCSI Standard, was approved in 1986. The newest SCSI innovation is currently LVD SCSI . Allows up to 5 mb per sec. data transfer rate. For lower data transfer rates Termination of each signal consists of 220 Ohms to Term Power Line and 330 Ohms to ground. Ideal Impedance match is 132 ohms.
Passive termination is the oldest method of termination.
Passive terminators simply provide impedance close to the impedance of the cable. This is a more stable form of terminating SCSI cables. Active terminators control the impedance at the end of the SCSI bus by using a voltage regulator, not just the power supplied by the SCSI card. This type of termination supports longer cable lengths and faster data transfer rates than does passive termination. There are 18 110-Ohm resistors, three or more capacitors, two voltage reference resistors, and one voltage regulator.