CAT-5 cables are the most common because it is widely used in telephone and data transmissions. Because of its twisted configuration, it offers good EMI immunity. Other cables can be used as long the electrical requirements for communication can be met. The most important requirement is to have cables with low capacitance. To maximize cable length, use a cable with specific capacitance of 15pF/m. For more information please read AN148 and The Book of iButton Standards.