Does this SCSI bus call for a passive CN50 terminator?
An unused port at the end of a SCSI chain may need a terminator, but its shape is only the first clue. Identify the controller, the last device, the connector and the kind of termination the manual specifies for that bus.
Read the termination requirement
The part shown here is a passive male Centronics 50 terminator. An LVD system that specifies active LVD termination needs a different part even if an adapter makes the shells fit. Check whether the enclosure already provides termination internally or through a setting.
Troubleshooting after removing a drive
Draw the original chain, mark both ends, and identify what changed when you took the drive away. Removing the last unit can also remove the point where the bus was terminated. Compare that change with the manual before replacing a working data cable.
Identify the end that moved
A new shelf added after a previously last device changes where the physical end of that bus sits. Before shopping, use the controller and enclosure diagrams to identify whether the former end contains a plug-in terminator, a built-in terminator controlled by a setting or a cable with its own termination. Note which of those components would move with the shelf. If you cannot tell from the back panel, the model number and manual are better evidence than how many sockets look empty. This prevents buying an extra plug when the existing installation already has the required termination hardware.
When the last external device is removed
Mark the two physical ends of the remaining bus after you remove the peripheral. A terminator left on the disconnected unit no longer terminates the chain still in use. Check whether the new last device already has termination enabled or whether the cable has a built-in terminator. The 30C2-05500 is specifically a passive CN50 male terminator. Confirm the bus requires that style and that its connector mates at the intended point. If the controller calls for active or LVD termination, a passive part with a matching shell does not satisfy that requirement.
Buying a terminator for equipment restored from several systems
A box of used SCSI devices can include several terminators with no clear record of which machine they served. Do not select a plug by the number of units in the box. First draw the system you intend to build, including the controller and each active cable segment. For each end on that drawing, identify the termination method required by its equipment documentation and the connector available there. Compare those two requirements with the markings and specification for each spare. If the markings are missing and the seller cannot establish the type, identify a documented part before committing an important drive to the rebuilt system.
A closer look at this part
SCSI Terminator, Centronics 50 (CN50) Male, One End, Passive
30C2-05500
- Connector references
- Centronics 50
- Configuration
- Passive
