Virtual TapeServer 6.03.41 Installation Guide

18 | Cabling and Connecting VTS
Cabling from NonStop S-series servers
NonStop S-series servers use HVD SCSI to connect to disk and tape peripherals. The NonStop
S-series server I/O controller uses a 68-pin high-density connector.
VTS uses low voltage differential (LVD) SCSI, so conversion of the NonStop S-series HVD
signal to LVD is required. To accomplish this task, VTS for NonStop S-series servers includes
one or more 1U (1.75 inch) VTS SCSI converters.
The SCSI converter converts high-voltage differential (HVD) Ultra160/SCSI-3 to low-voltage
differential (LVD) Ultra-2 SCSI. It provides four pairs of 68-pin connectors (all female). Each
pair consists of one 68-pin HVD connection (top row) and one 68-pin LVD connection (bottom
row). Up to four SCSI HVD connections can be converted to LVD SCSI for VTS usage. Up to
three SCSI converters come prepackaged with VTS.
The VTS SCSI converter connects to a NonStop S-series server in the same way as a physical
tape device, using a SCSI cable connected to controllers in the NonStop S-series server.
Cabling the NonStop S-series server to the SCSI converter
Connections are made to the PMF, IOMF, and/or ServerNet/DA. These controllers use a
female MD68 connector. The SCSI cable used to connect to the NonStop S-series server must
have a male MD68 connector. The other end must also have a male MD68 connector to plug
into the top row of female MD68 connectors on the VTS SCSI converter. Cable length to the
NonStop S-series server is limited to 25 meters (82 feet). Use high quality cables of the
shortest possible length based on the location of the equipment. PMF, IOMF, and ServerNet
controllers use external or pass-through termination where the cable plugs into the silver
terminator. The PMF 2 and IOMF 2 controllers use internal termination with the cable
plugging directly into the controller.
Checking SCSI termination
All VTS SCSI ports are internally terminated. Check that appropriate termination is
installed at the opposite end of the SCSI bus for all NonStop S-series servers and external
SCSI storage devices.