"The card itself has a 68 pin adapter."
Yes, but you should also have received a slot adapter (
item 3 shown here) with an HD50 which may be connected to
Point 2 on the photo. You should use this connector to attach your [slower] Zip drive, rather than use the ext 68 pin on the card. More on this below.
"It is larger than the normal 68 pin adapter that are found in most scsi systems."
Larger than an HD50 perhaps, but all 68-pin connectors are this size.
"Also from what I understand preserving the bandwidth is false. The devices do run independantly of one another. ie the scsi zip running at 10MB/sec will not effect my drives running at 80MB/sec. Unless I read wrong?"
The DC-390U2W has two independent channels...connectors 3 & 7 from the photo form the first channel which is Ultra2 (80MB/sec max), whereas connectors 1 & 2 form the second channel which is Ultra/Wide (40MB/sec max). The fact that it has two independent channels allows you to mix LVD and SE devices on the card and preserve their max bandwidth, but not on the same
channel. So it is best to keep your faster LVD Ultra2 devices on the first channel and the slower SE Fast/Wide devices on channel two.
Quote from the DC-390U2W manual:
"When any SE device is connected on the Ultra2 connector(s), all the LVD devices on the connector(s) will be down-graded to SE performance."
Best regards,
Floyd