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Convert Between LVD or Single-ended and HVD!Convert Between LVD or Single-ended and HVD
Extend Bus Length!Extend SE or LVD Bus Length
Isolate HVD Segments of a SCSI bus!Isolate HVD Segments of a SCSI bus

Stand-alone and Board-level Versions Available!Stand-alone and Board-level Versions

The board-level version Model MH17 is sized to fit in a standard 5.25 drive bay!

Targets and initiators may be located on both sides of the Expander!Targets and initiators may be located on both sides of the Expander

The models are backward compatible with older versions of SCSI!The models are backward compatible with older versions of SCSI

Does not consume a SCSI ID!Does not consume a SCSI ID


Custom Modifications to Your Specs. SCSI expander products and our newest LVD version. Includes: SCSI Converters/Extenders, Fiber Optic Extenders, SCSI Bus RegeneratoRs, SCSI ASICs, SCSI Quiet Cable and SCSI Cable Testers
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Relative Humidity: 0 - 95% non-condensing
Operating Temperature: 0 - 50°C
Storage Temperature: –25 to +75°C
Power Requirements
Stand-alone units (MH16A):
Voltage: 100 - 260 VAC, auto select
Frequency: 50 - 60 Hz
Board-level units (MH17A):
Voltage: 5 V dc ±5%
Current: 1.5 A max
Safety Approvals
FCC Class A, CE
SCSI Connections
MH16A, MH17A: SCSI-3 68-pin High-Density female Alt-3 “P” Connector
Sustained Data Throughput:
Limited by HVD bus to 40 MBytes/sec (16-bit)
Two year limited warranty
MH16A: approx. 12 oz (0.34 kg)
Shipping weight, approx. 4 lb (1.8 kg)
MH17A: 3.5 oz (99 g)
Shipping weight, approx. 2 lb (1 kg)
Physical Size (MH16A)
Height: 1.6 in. (41 mm)
Width: 4.1 in. (104 mm)
Depth: 4.5 in. (114 mm)
Board-Level Version Dimensions:
Overall board dimensions 4.00 x 3.88 in. (101.6 x 98.5 mm)
See PDF drawing for details.

Interconnect HVD with LVD/MSE Devices


Paralan’s models MH16A / MH17A let you add LVD devices into an existing High Voltage Differential (HVD) system, or utilize existing HVD devices in an LVD/MSE or single-ended system. All this is accomplished without any impact on SCSI protocol or loss of data thruput.

Using LVD/MSE Devices in an Existing HVD System

SCSI protocol allows all SCSI implementations i.e. LVD/SE/HVD to communicate on the same bus domain. This is accomplished through the use of the DIFFSENSE signal. However, the performance level is reduced by the slower devices on each segment. This huge penalty is avoided by using a type of SCSI Expander usually referred to as a Converter. As an example; a SCSI converter is placed between an LVD device and an HVD device. This isolates the different versions of SCSI into two segments allowing both the LVD devices and the HVD devices to function at their full thruput.

Using LVD/MSE Devices in an Existing HVD System!
Using HVD (High Voltage Differential) Devices in an LVD/MSE System

HVD Devices can be added to an LVD/MSE or Single-ended system simply by adding a LVD/MSE to HVD Converter, attaching the HVD SCSI segment to the HVD port of the Converter. The Converter will not consume a SCSI ID, and the system will operate with no compromise of thruput.

Using HVD (High Voltage Differential) Devices in an LVD/MSE System!
Mixing SCSI Device Types

Multimode LVD SCSI will automatically change to Single-Ended (SE) if an SE device is on the same bus segment. However, neither LVD nor SE SCSI can directly communicate with HVD SCSI. A Model MH16A or MH17A LVD/MSE to HVD SCSI Converter enables this type of communication by converting the LVD or SE SCSI to HVD or vice versa. The presence of a SCSI Converter will not decrease data thruput.

If the application in which you want to use an LVD/MSE to HVD converter has an Ultra320 LVD host adapter with Ultra320 drives connected to it, you should use the Model MH32A or MH33A. In all other LVD or SE to HVD applications the Model MH32A, MH33A, MH16A or MH17A may be used.

Paralan Models MH16A and MH17A LVD/MSE to HVD SCSI Converters are completely compatible with all devices that conform to the full ANSI X3T10 standards through SPI-3 (Ultra160). They are available either as stand-alone units utilizing line voltage, or as board-level units for installation in other equipment.

Isolation for Hot Swapping

The logical isolation between the two sides of a SCSI Converter allows a device on one side to be disconnected without disturbing the other side.

Narrow/Wide Conversion

The MH16A and MH17A (Wide) models may be used to interconnect Narrow SCSI devices on one side with Wide SCSI on the other side.



Ordering Guide
Model Numbers SCSI Product Description
Stand-alone Board Version   
SCSI Wide LVD/MSE to HVD Converter (16-bit)
Rack Mount Expander Box (rack mount up to 3 SCSI Expanders)
5-1/4" Half Height Drive Bay Mounting Bracket & Faceplate for MH17A
SCSI Quiet Cable™   (specify length)


9 TO 5 COMPUTER: Global Value-Added Distribution of NEW, used and refurbished computer periphery by a family-owned and operated company since 1979- distributing internationally computer related peripherals on the new, used and refurbished levels. HP, Compaq, IBM, CISCO, 3COM, APPLE, SEAGATE, and other major branded products as well as a MAJOR focus on Mass Storage related drives, media, storage racks, tri-optic barcode labels, libraries, autoloaders, duplicators, jukeboxes, HBA's, JBOD, Raid, SAN, NAS and software solutions.

As our stock of NEW, used and refurbished storage equipment changes daily, be sure to use our online chat service to get "real time" pricing from a knowledgeable sales technician. We also offer the lowest priced storage media on the net. Contact us now for drive rental, repair, duplication, software solutions or professional consultation.

*Buying refurbished can be better than buying new because flaws have been found and fixed, once it is deemed to be complete and in good working order it is repackaged to be sold at a lower price as refurbished.

© Copyright 2003.
*Price and availabilities subject to change without any notice. Not responsible for typographical errors.