| 1 | Interface and SCSI generation | Confirm the SCSI interface, transfer mode, and device documentation before selecting a cable. | Parallel SCSI, SAS, and other storage interfaces are not interchangeable. Match the cable to the host adapter and every connected device. |
| 2 | Cable length | Check the maximum permitted bus length for the exact SCSI type, speed, and electrical mode. | Length limits vary. As a general reference, many LVD parallel SCSI configurations allow up to 12 m, while fast single-ended configurations commonly have shorter limits, often around 3 m. Count internal and external cable sections together and follow the applicable specifications. |
| 3 | Connector type and pin count | Identify both connector shapes, pin counts, gender, and required cable direction. | Common parallel SCSI connectors include 50-pin and 68-pin types, with multiple physical formats. Do not rely on pin count alone; check that the connector fits and has the correct wiring and pinout. |
| 4 | Electrical mode and device compatibility | Verify whether the bus uses single-ended (SE), low-voltage differential (LVD), or high-voltage differential (HVD) signaling. | These signaling modes are not universally compatible. Some mixed SE/LVD setups may operate in SE mode, which can reduce the available speed and cable-length limit. Confirm compatibility across the entire bus. |
| 5 | Shielding and signal integrity | Look for a properly shielded cable assembly, secure connector shells, and construction intended for the relevant SCSI signaling mode. | Shielding can help reduce electromagnetic interference, but it cannot compensate for an out-of-spec cable, excessive length, poor routing, or incorrect termination. |
| 6 | Termination and bus layout | Check how the bus will be terminated and whether the cable layout supports the required topology. | A parallel SCSI bus generally needs termination at its two physical ends, not at intermediate points. Avoid unterminated branches and confirm whether termination is provided by a device, adapter, or separate terminator. |
| 7 | Build quality and installation conditions | Inspect connector retention, strain relief, conductor consistency, and suitability for the installation environment. | Choose a cable that can be routed without sharp bends, crushing, or tension on the connectors. Keep it away from strong interference sources where practical, and follow the cable maker’s handling and bend-radius guidance. |