C141-C015
27
1.3.2 Interface
cable
Use the twisted-pair interface cables satisfying the requirements of Tables 1.4 and 1.5.
Table 1.4
SE and LVD Transmission line impedance of cable at maximum indicated data transfer
rate
Local SE transmission line
impedance
Local differential
transmission line impedance
Description
Minimum Maximum Minimum
Maximum
All
84 Ohms (78
Ohms) (Note)
96 Ohms
110 Ohms
135 Ohms
Note:
If SCSI loads attached to the cable media are separated by more than 1.0 m use the value of 78
Ohms.
Table 1.5
Attenuation Requiaments for SCSI cable media
Distance between
SCSI bus
terminators (meters)
Distances are consistent with these
minimum size conductors when used
with high quality dielectrics
Notes
0 to 9
0.0324 mm
2
(32 AWG) solid/
0.05092 mm
2
(30 AWG) stranded
multiple loads allowed
0 to 12
0.05092 mm
2
(30 AWG) solid/
0.08042 mm
2
(28 AWG) stranded
multiple loads allowed
>12 to 25
0.05092 mm
2
(30 AWG) solid/
0.08042 mm
2
(28 AWG) stranded
point to point only
A twisted-pair cable must consist of pin n and pin n+1 (where "n" is an odd number) of the
interface connector. Use the SCSI bus cables having the same impedance characteristics to
minimize the signal reflection but keep the highest possible transmission characteristics.
If SCSI devices are connected to the terminals other than the interface cable ends, use the cable
branch at the SCSI connectors. No more SCSI cable can be connected to the last SCSI device
(which is connected to the SCSI bus) except when it is terminated with the terminator (see Figure
1.11).
The interface cable must have the stub length less than 0.1 meter for the single-ended SCSI cable.
Separate the stabs at least 0.3 meter from each other. (Keep the stab at least 30 cm away from a
SCSI device.)
Summary of Contents for MBA3300 NP SERIES
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Page 69: ...C141 C015 63 Figure 1 26 ARBITRATION phase ...
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Page 117: ...1 37 C141 C007 Figure 1 43 Bus phase sequence 1 of 2 ...
Page 118: ...38 C141 C015 Figure 1 43 Bus phase sequence 2 of 2 ...
Page 128: ...48 C141 C015 Figure 1 47 SPI information unit sequence during initial connection ...
Page 129: ...1 49 C141 C007 Figure 1 48 SPI information unit sequence during data type transfers ...
Page 130: ...50 C141 C015 Figure 1 49 SPI information unit sequence during data stream type transfers ...
Page 131: ...1 51 C141 C007 Figure 1 50 SPI information unit sequence during status transfers ...
Page 155: ...1 75 C141 C007 Figure 1 56 Connection to the LVD receivers ...
Page 161: ...Figure 2 1 Message format 154 C141 C015 ...
Page 166: ...Figure 2 2 SCSI pointer configuration C141 C015 159 ...
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