2)Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1-Wire recovery times. The specified value here applies to systems with only one device and with the minimum 1-Wire recovery times. For more heavily loaded systems, an active pullup such as that found in the DS2480B may be required.
3)
Capacitance on IO could be 800pF when power is first applied. If a 2.2kΩ resistor is used to pull up the data line, 2.5μs after VPUP has been applied the parasite capacitor will not affect normal communication.