LOW VOLTAGE DIFFERENTIAL (LVD, LVD/SE, Ultra2, Ultra3/160) – the NEW high speed SCSI protocol for transfer rates up to 160Mb/s adds speed, distance, and connectivity to the SCSI bus. Requires LVD or LVD/SE (multi-mode) termination.
ACTIVE NEGATION – similar to “ACTIVE”, but uses a more complex circuit to ensure a stabilized voltage level supply, thereby allowing for a “cleaner”, noise-free SCSI signal. Active Negation is the accepted standard of termination for “Ultra SCSI”. *ACTIVE – also known as “regulated” or “Alt II”, incorporates a voltage regulator circuit to supply a regulated voltage level to the terminating resistors, is considered a much more reliable terminator than the passive, and is used on FAST SCSI devices.
DIFFERENTIAL – used exclusively for HVD High Voltage Differential SCSI drive subsystems, is available for either 50-pin (narrow) SCSI or 68-pin (wide) SCSI. Utilizes a 150/330 ohm resistor circuit to terminate. Allows for longer SCSI bus lengths.
PASSIVE – considered the low end of SCSI termination performance, with a series of 220/330 ohm terminating resistors. Typically used on SCSI-1 and slower SCSI-2.
FORCED PERFECT (FPT) – utilizes a circuit containing a resistor/diode combination to create an “impedance matching” terminator.
FPT 18-Line – has FPT circuitry on all 18 signal lines,and is also “regulated”. (for 50-pin single-ended SCSI only)