Scsi Bus Connections - Dawicontrol DC-29160 U3W Mode D'emploi

Manual
At least one device of the SCSI bus must supply the termination power
(TERMPWR) of 5 volts required for correct termination. In general, the DC-29160 U3W
will do this.
The diagram depicts a properly installed and correctly terminated LVD SCSI bus.

4.3. SCSI Bus Connections

The SCSI devices are connected to the SCSI host adapter via suitable cables.
Make sure the LVD cables correspond with the SCSI specifications. As to the length
of the cables, the following restrictions apply; the combined length of the internal and
external cables may not exceed the prescribed maximum cable length:
SCSI type SCSI extension
SCSI 1
SCSI 2 FAST
SCSI 3 ULTRA
SCSI 3 ULTRA
SCSI 3 ULTRA WIDE
SCSI 3 ULTRA WIDE
SCSI 3 ULTRA 2 WIDE (LVD)
SCSI 3 ULTRA 3 WIDE (LVD) 160 MByte/s
SCSI 3 ULTRA 3 WIDE (LVD) 160 MByte/s
Basically, cables should be as short as possible and only as long as necessary!
When using cable adapters for connecting, for instance, a 50-pole cable to a 68 pole
connection, these transitions can further reduce cable length due to circuit loss.
The DC-29160 U3W only admits two or three simultaneous connections, as the
SCSI bus has to represent a chain of two (and not more) ends. Using all the
connections creates a so-called stem formation or T-junction; these are strictly
forbidden and cause a complete collapse of the SCSI system.
When connecting an ULTRA WIDE device to the DC-29160 U3W, the host
adapter will switch to single end mode, which means that the maximum cable length
can be reduced to 1,5 m depending on the number of devices used and the transfer
rate! Please take into account these restrictions and the installation will cause you no
problems.
transferrate devices max. cable length
5 MByte/s 7
10 MByte/s 7
20 MByte/s 3
20 MByte/s 7
40 MByte/s 3
40 MByte/s 15
80 MByte/s 15
1
15
- 35 -
6,0 m
3,0 m
3,0 m
1,5 m
3,0 m
1,5 m
12,0 m
25,0 m
12,0 m