Where can I get an extension cable for the Altec Lansing ADA-305 speakers?

I recently picked up a set of old Altec Lansing ADA-305 speakers with subwoofer. They work great, but the right and left speakers cables are a bit short. They're not regular 3.5mm speaker wire. They kind've seem to be like a 5 pin mini-din but with an arrangement of 3 pins on one side and 2 on the other, not 5 across the top like a MIDI cable. Anyone have any ideas?