Prarietech, yes, the DS2482 is driving the line the whole distance. Also keep in mind that some of the time the driver chip is driving the wire, and sometimes the DS18B20 is driving the wire, so the devices at each end have to be able to drive the whole distance at some point in time. This is why the driver chip and sensors are powered from 5 volts instead of 3v3. This is also the reason that I use a driver chip, and do not drive from the GPIO pin directly. The driver chip also protects the GPIO pin in case a transient were to find its way back down the line towards the Pi.
Because the DS18B20's also have to drive the line the whole way back that I put a capacitor at each sensor (10ufd/16v tantalum). The capacitor supplies an extra bit of power to the sensor (right AT the sensor - this is important) when needed to drive the line.
Each sensor was wired like the pic, and a regular RJ45 plug attached to to a pigtail on the sensor per AT568B. The keystone is wired the same way, so sensors can be added/removed/replaced as needed just by plugging them in. Note that in the picture that the keystone is just tapped into the line. I stripped about four inches of insulation off, separated the wires and carefully punched it down. This effectively puts all of the sensors in parallel. My installation has five keystones along the 369 foot length. Along this length, there is a sensor at the end, and ones spaced at about ~340, ~320, ~300 and ~280 foot marks from the driver chip. The far end of the wire goes to the DS2482 (data wires), and of course +5 and ground.
When I was initially designing and testing this, I was using 470 feet of CAT6 wire, and it worked perfectly at that distance too.
The first pic shows the soldering detail of one sensor. An 8 inch pigtail was being soldered onto the sensor.
The second pic shows the keystone tap detail. I took this when I was doing the actual installation.