What is this?

["Jason Whorton" <jason@microxl.com>]

Hello.  I have an Apple II hardware item, and I am not sure what it is.  I
think it is a device to allow AppleTalk sharing of an ImageWriter II, but I
want to find out for certain.  I bought an ImageWriter II and it was
connected to the back at the 8-pin Mini-DIN connector.  The device is an
Apple product with the part number 590-0565-A.  It has an 8-pin Mini-DIN
connector on one end of an approximately 24" cable and a small box 1" X 1.5"
X 2" with two round four-pin connectors (though the large pin of the group
appears to only be hollow on the inside, with no electrical connection) with
each one having a pair of arrows on top to label them.  One arrow in each
pair points up and one points down.
    If anyone can tell me what it is, I would really appreciate it.

Thank you,
Jason Whorton