Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 109

Depending on the model, your computer may include one of the
SCSI cables shown in the next illustration.
Because your computer comes preconfigured, cable
configuration does not become a consideration until you decide
to add an optional SCSI device.
Computers with 2-peripheral SCSI cables (without
termination) must have termination enabled on the last
device.
Computers with 3- and 4-peripheral SCSI cables come with a
terminator on the end of the cable. The connector on the
opposite end of the cable always connects to the system
board. All SCSI devices connected with these cables must
have their termination disabled.
4X and 8X devices may not have terminating jumpers on
the device. Termination on these devices must be
achieved with terminated cable.