Zip100 identification tips: These are two non-exhaustive examples; there are others I do not own, such as the auto sensing zip plus model which is identifiable by the front bezel label under the eject button-

Zip 100 SCSI

Model number is on the bottom label and is Z100S2

No label above power connector in recess

Both rear DB25s are female

Primary one left side viewed from rear is labeled zip

Daisy chain output connector labeled with diamond-dash SCSI symbol

Two slide switches between DB25s for terminator and SCSI ID setting

Zip 100 Parallel

Model number is above the power connector in the recess and is Z100P2

Label on bottom shows connections but no model number

Left rear DB25 is male, right rear DB25 is female (viewed from the rear)

Left side male primary connector is labeled zip

Right side female daisy chain to printer labeled with printer symbol

No other configuration switches anywhere