For a printable version, please see the PDF of this data sheet.

Extending the Bus Length

There are several ways to utilize Expanders to extend the SCSI bus length well past standard SCSI limits. Some examples:

Using a single Multimode Expander – The effective bus length can be doubled by the addition of a single Multimode Expander. With all LVD devices, the standard 12m (40 ft) bus length can be extended to 24m (80 feet).

Multimode LVD SCSI will automatically change to Single-Ended (SE) if an SE device is on the bus segment. When both LVD and SE devices share the same bus segment, the entire SCSI bus segment will operate at the lower performance level of single-ended SCSI, including reduced bus length. However, by grouping LVD and SE devices, and isolating them with a Multimode Expander, the LVD devices can be operated at their full designed thru put levels.

Cable causes timing delays of approximately 1.5 ns per foot of length. When SCSI-specified cable length is exceeded, this cable-caused delay would normally cause a system to malfunction. Logic circuitry in the Expander manages this delay such that disconnect, reconnect, arbitration and all other SCSI features are not affected. The SCSI signals are regenerated, reshaped, and retransmitted, all transparent to the system.

Paralan Expanders are completely compatible with all devices that conform to the full ANSI X3T10 standard. They are available either as stand-alone units utilizing wall power, or as board-level units for installation in other equipment.

Isolation for Hot Swapping

The logical isolation between the two sides of an Expander allows a device on side B, for example, to be disconnected without disturbing side A.

Narrow/Wide Conversion

The MM16 and MM17 (wide) models may be used to interconnect narrow SCSI devices on side B, for example with wide SCSI on side A.

High Voltage Differential (HVD) SCSI Extenders and Converters

Paralan also has Converters (Paralan MHxx models) for converting between High Voltage Differential (HVD) and LVD or single-ended SCSI devices. Converters may also be used to provide extension of an LVD or single-ended bus up to 50m (160 feet).
To extend an existing HVD bus, see the data sheet for Paralan’s SIR-D16 RegeneratoR™.