Token Ring - is a MAU required?

Solution 1:

The other answer already says this, but not very clearly.

Token Ring networks always have a single physical ring that the electrical signal travels along, going from one network adapter to the next until it gets back around to the start. There is no (traditional) way to get around this topology.

Originally Token Ring NICs simply had a wire running from one machine to the next, in daisy chain style. If one of the NICs had a problem however it would interrupt the ring and problems ensued.

To get around these single points of failure and the fact that you had to wire from one machine to the next constantly, MAUs were invented. They allow a wire (actually two wires, down and up) to run from the machines to the MAU. The MAU would simply connect one active machine to the next. If a machine was not "active" then the data signals would skip that port and go to the next.

(Picture stolen from Wikipedia) You can easily imagine how this would have to be wired without the MAU. The wiring would simply follow the black lines as shown in the drawing.

Solution 2:

In Token Ring, the logical infrastructure view is always a ring/open ring (depending on how you want to look at it).

MAUs just hide it and make a ring inside the device. With a single-wire configuration you only need resistors on the ends of the cable, but when one station disconnects, whole network goes down, unlike with a MAU.