X3T9.2/91-49 Rev 1 April 18, 1991 Rev 1: April 25, 1991 To: X3T9.2 Committee From: John Lohmeyer, NCR Principal Member of X3T9.2 Subject: SCSI Bus Type Identification Rev 1: Revision 0 was reviewed by the April '91 plenary group. They requested several changes which are included in revision 1. As we have more systems in-house which may either use single-ended drivers or differential drivers, a problem has developed in quickly identifying the driver type which is present. Some visual means to identify the driver type would be beneficial to technicians in our organization. End users would probably also benefit. I propose that an optional clause be included in the SCSI-3 Physical Interface document recommending standard labels for those who wish to use them. The following paragraphs would fulfill our need: " It is recommended that SCSI devices include some means (e.g., labels) to identify the type of drivers and receivers employed and the cable type (especially valuable in the case of a 68-position connector). Such means should be located near the device connector. The recommended driver and receiver identifications are: "SCSI-SE" Identifies a device that uses single-ended drivers and receivers. "SCSI-DF" Identifies a device that uses differential drivers and receivers. "SCSI" Identifies an SCSI device. This label would be used on devices that do not identify the the type of drivers and receivers employed (e.g., the driver and receiver type depends on some internal configuration option). Implementors wishing to identify the cable type should postfix a hyphen and the uppercase cable type letter (e.g., "SCSI-SE-P" for a single-ended P cable connector). "