It might feel O.K. – but still be completely wrong

Suppose that you were getting ready to print a handout for your presentation, but found your toner was low. You unplugged the cable on the back of your printer so you could pull it out. Then you put in a new toner cartridge, and plugged the printer cable back in. But now it didn’t work. What could have gone wrong?

You might have incorrectly plugged your printer cable into the network jack. At Computerworld in Shark Tank on there was an article on August 2, 2019 titled There are only so many shapes which described that sequence. As is shown above, the USB Type B plug used for the printer can physically fit into an 8P8C Ethernet network jack. (I have shown the end of a plug and an inline coupler).

It feels right, but it does not look right at all. The jack is much wider than the plug, and has a different shape. Also, that type B plug has four pins on the interior, while the network jack has a row with eight pins at the bottom. Nothing matches electrically.

How could you prevent that problem - eliminate having a worst moment? If you are not using the network jack, then you could put a piece of masking tape or black electrical tape over it as a lock out device. Back on February 18, 2011 I had blogged about More on mistake proofing: lock out what you don’t want to happen.

  

Conversely it is possible to misassemble metric and inch dimensioned bolts and nuts that may look right but won’t feel right. The mixed combinations shown above in two tables (from an article by Guy Avelon) will be too loose and not have the expected strength.