Specifications

I
SP-3 SCSI Interface Manual
I
SCSI Terminators
The SCSI terminator is simply a resistor network on each SCSI signal on the SCSI bus. The
terminator prevents reflection or ringing on the signal lines, allowing reliable high speed data
transfers.
Warning! ” A system configuration (two or more SCSI Storage
Devices) must have two terminators. Damage will result if more than?,
two.ferniinators are present. Terminator placement is described below.
The terminator is usually implemented in one of two ways: either externally or internally. The
external terminator resembles either two 50-pin SCSI connectors mounted back to back, or one
50-pin SCSI connector that is connected to the same SCSI Storage Device with two connectors on
it. The two-connector type of terminator is plugged into the SCSI connector of the SCSI Storage
Device and then the SCSI cable is plugged into the terminator. The single-connector SCSI
terminator is plugged into the unused connector on a two-connector SCSI Storage Device. The
internal terminator is simply the resistor network integrated into the SCSI Storage Device itself,
typically as resistor packs on the SCSI device controller circuit board. The documentation that
accompanies the SCSI Storage Device will usually describe the procedures required for
installation and removal of terminators. The SCSI installed in the ASR-10 rack mount (or the 9-3
SCSI Kit for the ASR-10 keyboard version) contains internal termination via removable resistor
packs. Note that the ASR-10 supplies power for its own terminator only. Therefore, any SCSI
Storage Devices used with the ASR-10 must supply power to the SCSI bus.
Connecting your ASR-10 to a SCSI Storage Device
Each time you set up or break down your ASR-10 and SCSI Storage Device system, you will need
to connect or disconnect the SCSI cable from the 25-pin connector on the rear of the ASR-10, and
probably from the SCSI Storage Device as well. When doing this, be careful to avoid static
discharges that could damage either piece of equipment. Also make sure that you do not bend
the SCSI cable too sharply, which could damage some of the small wires inside the cable and
make it unreliable. If you transport the system a lot, it is a good idea to carry an extra SCSI cable, just in
case.
ENSONIQ ASR-10 Version 3 Operating System
109