Scsi - HP 743 Service Handbook

SCSI

The built-in SCSI-2 port is implemented using an NCR710 macrocell inside the I/O ASIC
chip. This 8-bit single ended implementation is compatible with the current Series 700
products and supports 5 Mbytes/sec data transfer rates.
The SCSI bus is terminated to 3.3 volts through 127 Ohms. on the system board. If the
board computer is used in a VMEbus chassis having internal mass storage devices, those
devices must have their terminator removed. If an external disk drive is used, an active ter-
minator must be used on the last drive's uncabled connector.
Table 2-12 shows the SCSI interface specifications.
Table 2-12
Type:
Data Rate:
Device Limits:
Connector Type:
Maximum External
Cable Length:
Controller:
Figure 2-7 shows the SCSI connector.
Figure 2-7
SCSI Interface Specifications
SCSI-II (ANSI x3.131-1986), 8-bit, single-ended
Synchronous - 5MBytes/second
7 internal and/or external peripherals
Note: The CPU is considered one device.
SCSI-II, ALT-1 50-pin high-density thumbscrew
4 meters (13.1 feet)
NCR 53C710 compatible macrocell, Rev. D.
SCSI Connector
Functional Description
Built-in Interfaces
2-17