I came across a page which explains bipolar transistors which are used to implement wired-and logic. It says
Another feature of DTL is its ability to implement a "wired AND" function. For example, if we wired several DTL NAND gates together, we would observe the following behavior. If any one of the NAND gates had a logic 0 as its output, the whole output function would also be at a logic 0 voltage. All the output functions would have to be at logic 1 for the output to be 1. See Figure B.9, which shows the internal wiring and the equivalent logic schematic for the wired AND function.
Looking at the figure, I see that, it all inputs (three gate inputs) are logical 0, then the output is logical 1 due to the pullup resistors. On the other hand, if any of the inputs (or all) is (are) logical 1, then the output will be zero because there is a connection between output and ground. So, it it actually implements wired-nand!
Any explanation for that?