The external connector is electrically quite similar to the internal connector (which supports two drives). You will need to make a cable with a 37 pin male connector, similar to your internal cable. Typically, that would include a twist, but there are ways around that. The pin-out of the cable (Tech Ref p1-182): Unused 1-5 Index 6 Motor Enable C 7 Drive Select D 8 Drive Select C 9 Motor Enable D 10 Direction 11 Step Pulse 12 Write Data 13 Write Enable 14 Track 0 15 Write protect 16 Read Data 17 Side Select 18 Ground 20-37 Because of the difference in how pins are numbered on D connectors v dual row headers or card edges, that may seem completely scrambled. But if you sketch it out, you'll see that you can get away with crimping a 37 pin D Male onto an ordinbary PC drive cable. (BUT, align pin 34 of the cable with the 19/37 end of the D connector!!) If you make up such a cable, then jumper your external drives as "B:", just like you do for internals. In addition, if you want to do it "right", turn off positions 7 and 8 of the 5150 configuration dip switch, so that the PC will know that it has 4 floppies. Hard drive letters, etc. will then begin at E:. Otherwise, with DOS >= 3.20, you could access the external drives with use of 2 inclusions of DRIVER.SYS (/D:2, and /D:3), which will insert the drive letters for your extra floppies AFTER your hard drives, etc. -- Fred Cisin cisin(a)xenosoft.com XenoSoft http://www.xenosoft.com 2210 Sixth St. (510) 644-9366 Berkeley, CA 94710-2219