I always thought a printer cable was just a printer cable.

I have one laser printer connected to two XP computers. I have known for many months that the printer functioned differently, depending on which computer to which it was connected. I assumed the differences were caused by the computer. After trying all types of computer and printer adjustments, I concluded that the differences were due to the printer cables.

I want to purchase another cable, just like the one that works. Took both cables to Radio Shack. Young lady said that there is a difference, but could not identify the difference by name. So, if I do not know the name, I cannot shop for it.

The cable that works has an oblong-shaped feature in the linear middle of the cable, a little less than 3/4 inch in diameter and maybe 1 1/4 inch in circumference and 1 1/4 inch in length. Radio Shack lady says that this is what makes this printer cable work differently from the other printer cable.

Assuming she is correct, what do I shop for when looking for a printer cable?