Reliable SCSI card for G4 tower (Quicksilver or other G4 tower) with OS 9 ?

Question

Good morning.
I am trying to setup a G4 Quicksilver (or another slower G4 tower) under OS 9 to be able to use a very nice Epson wide format scanner (no OS X drivers available). It has only a SCSI Centronics 50 pin connector.
1. Is there a reliable and available (with OS 9 drivers) SCSI PCI card that will work in a variety of G4 towers under OS 9?
2. If the card doesn't have the 50 pin Centronics connector, how do I adapt the scanner to the card input?
Thanks for your time.

Answer 1

When SCSI was built in to Macs, it was what we now call "narrow" SCSI. Apple used the DB-25, a 25-pin connector that looked like an RS-232 connector (because it was the same connector). To use it with typical 50-pin Centronics devices, a cable called a Macintosh System Cable was used. The Macintosh System cable swapped the signals around and connected the few grounds in the 25-pin connector to the many grounds in the 50-pin connector. Almost all devices came with two Centronics-50 connectors. Connecting multiple devices together was accomplished with a Centronics-50-to-Centronics-50 cable, and the last connector on the last device was filed with a Terminator.
Most of the add-on cards available later were "fast", "wide", "fast and wide" SCSI, optimized and tuned up to run faster than the built-in's maximum 5 Mega Bytes/sec. They used more complex cables and had more rules for proper operation. Your scanner alone cannot generate data fast enough to fill up the original "narrow" SCSI. So you need none of the later stuff.
Faced with no SCSI port on the new Blue & White G3 (the first Mac without a SCSI port since the original Macs), many users at that time installed the Adaptec 2930 card in a PCI slot to run their scanners or occasional other SCSI devices. The card is capable of Fast-20 speeds if your device supports it, and works with G3s and G4s with PCI slots. The card has an external 50-pin connector called HP-DB50, which has nothing to do with Hewlett Packard, it means Half-Pitch (the pins are twice as close together as on the DB-25 connector). HP-DB50-to-Centronics-50 cables are readily available. Support for the Adaptec 2930 is still available built into Mac OS X.
If you go with the Adaptec 2930 card, it will run your scanner, not require any adapters -- just one cable converts to the connector you need, and if you can get an "active" 50-pin Centronics terminator with an LED, your life should be easy.
There are tons more solutions available. Each comes with a little more added complexity and more potential features if you want to do additional things with it.