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In LVDS-Mode, an SE signal wire and its associated SE ground wire (GND) build a differen-

tial pair. Therefore, please take care when choosing an external round cable. It has to be

explicitly designed for LVDS. Very often all GND wires are put together in the connector.

These kinds of cables must not be used for LVDS.

 80MB/sec. synchronous data transfer rates

 Up to 12 Meters cable length

 Compatibility to Ultra SCSI and FAST SCSI devices

The Wide/Ultra2 ICP Controllers of the RD Series are available with 1, 2, 3 or 5 completely

independent Wide/Ultra2 SCSI channels. Each channel can control up to 15 Wide/Ultra2

SCSI devices.

In addition all Wide/Ultra2 ICP Controllers of the RD Series have a separate Narrow/Ultra

SCSI Channel for legacy SE SCSI devices (hard disks, CD-ROMs, DLTs, DATs, etc.).

SE SCSI devices of a certain installation should be operated with this channel. Thus, the

valuable Wide/Ultra2 SCSI channels are free for real Ultra2 SCSI devices (as soon as a SE

SCSI device is operated with a Wide/Ultra2 channel, the channel is automatically switched

to SE).

It is very important for you to observe the information and notes given in this section of the

User’s Manual because it helps to ensure that the SCSI devices that are used in connection

with the ICP Controllers are operated in a successful, long-lasting and trouble-free manner.

In many cases, this information is not only applicable to ICP Controllers, but in general to

all those SCSI systems which, like the ICP Controllers, use Wide/Ultra2 technology. Ac-

cording to its definition, the SCSI bus provides access to several participants that are

physically connected through an appropriate SCSI bus cable. To achieve a sufficiently good

signal quality, it is not only recommended to use very good cables and connectors, but also

to terminate both ends of the cable properly. For an unambiguous identification on the

bus, all participants have a unique number – the so-called SCSI-ID. Further details on these

topics can be found on the following pages.

Please note that

98% of all SCSI-related problems are caused by bad SCSI cables,

wrong SCSI bus termination and duplicate SCSI-IDs.

%6&6,&DEOHV

The quality and overall length of the cable, as well as the number and quality of the SCSI

connectors is very important for both internal and external SCSI cables. Generally, internal

SCSI cables are 50 or 68 conductor flat ribbon cables. To connect external SCSI devices,

round and shielded cables with appropriate connectors are typically used. External round

cables should have a SCSI-compliant placement of the inside conductors and should be

approved for LVDS operation. Besides the cables, the right connectors for a cable are also

very important. It is highly recommend to use highest quality connectors, only.

The following table shows the maximum cable lengths allowed for a given transfer rate.

Based on many years of SCSI experience, the lengths we recommend are in some cases

shorter than theoretically possible. The information in the table refers to one SCSI channel

and represent the overall length of the cable, including internal and external parts.

SCSI Bus

Width

SCSI Mode Bus-Type Synchronous

Data Transfer

Rate

Number of

devices

Max. Ca-

ble

Length

8 Bit, narrow Fast SE 10 MB/sec. 7 2.0 meters

8 Bit, narrow Fast-20, Ultra SE 20 MB/sec. 4 1.5 meters

8 Bit, narrow Fast-40, Ultra2 LVDS 40 MB/sec. 7 12 meters

1 2 ... 28 29 30 31 32 33 34 35 36 37 38 ... 217 218

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