Paralan has many options to reliably extend the SCSI bus to wherever your peripherals are located.

SCSI is limited by design to short transmission distances, but Paralan has developed a number of methods to extend the SCSI bus length:

Single-ended SCSI is particularly short, with 6 m (less than 20 feet) end-to-end for a normal SCSI bus, 3 m (10 feet) for fast SCSI, and only 1.5 m (5 feet) for Ultra SCSI applications. LVD (Low Voltage Differential) SCSI has a 12-m (40-ft) limit, but only when all attached devices are LVD. Standard Differential SCSI (HVD) is suitable for longer distances, up to 25 m (82 feet), but HVD SCSI is not universally supported and was rendered obsolete in the SPI-3 document of SCSI-3.

Paralan can match your SCSI needs with custom SCSI components, modifications to standard Paralan products, or even with custom systems! Paralan is ready to meet your exact requirements by applying our SCSI-savvy engineering - from SASI through Ultra320.

Single-ended SCSI Transmission Limits

Unassisted Single-ended SCSI: 6 m (19 feet); 3 m (10 feet) for fast SCSI; 1.5 m (5 feet) for Ultra SCSI

Adding a SCSI RegeneratoR™ doubles the distance to 3-12 m (10-40 feet)

Adding two SCSI RegeneratoR™s more than quadruples the distance to 15-25 m (50-80 feet)

Two Paralan Differential (HVD) SCSI Converters used as extenders: 45 m (140 feet)

Low-voltage Differential (LVD) SCSI Transmission Limits

Unassisted LVD SCSI: 12m (40 feet), or 25m (82 feet) point-to-point.
- Note: all devices on segment must be LVD, otherwise use Single-ended limits.

Adding one LVD/MSE Expander doubles the distance to 24 m (80 feet) or 50 m (164 feet)

Two Paralan LVD/MSE to HVD Converters used as extenders: 74m (240 ft)

High-voltage Differential (HVD) SCSI Transmission Limits

Unassisted differential SCSI: 25 m (82 feet)

Adding a SCSI RegeneratoR™ doubles the distance to 50 m (164 feet)

Adding two SCSI RegeneratoR™s quadruples the distance to 85 m (280 feet)

With Paralan Differential SCSI Converters: 750m (2500 feet)

For a discussion of SCSI Extenders and other expander techniques, see Marc Brooks' article for Computer Technology Review, The Case for SCSI Expanders. or Expanding the SCSI Bus for important information regarding different SCSI interfaces.