times for each digit on the dial. The number of pulses sent for each digit depends on the type of dial system used, which have traditionally varied by country, or by the manufacturer of the telephone system. For example, Sweden uses one pulse to signal the number zero, and ten pulses to signal the number nine. In Finland, where many phones were of Swedish manufacture, one pulse signaled number 1, and ten pulses number zero. New Zealand used ten pulses minus the number desired; so dialing the digit 7 produces three pulses. In Norway, the North American system with the number 1 corresponding to one pulse was used, except for the capital, Oslo, which used the same "inverse" system as in New Zealand. The sequencing of the digits on the dial varies accordingly. Rotary dials have no redial feature; the entire number must be dialed for every attempted call. Additionally, the time it took to dial a number depended on how far the dial had to travel to return to the resting position. A phone number that had digits that required larger numbers of pulses could be tedious to use, by comparison. Construction A rotary dial typically features a circular construction. The shaft that actuates the mechanical switching mechanism is driven by the finger wheel, a disk that has ten finger holes aligned close to the circumference. The finger wheel may be transparent or opaque permitting the viewing of the face plate, or number plate below, either in whole, or only showing the number assignment for each finger hole. The faceplate is printed with numbers, and sometimes letters, corresponding to each finger hole. The 1 is normally set at approximately 60 degrees clockwise from the uppermost point of the dial, or approximately at the 2 o'clock position, and then the numbers progress counterclockwise, with the 0 being at about 5 o'clock. A curved device called a finger stop sits above the dial at approximately the 4 o'clock position. The physical nature of the dialing mechanism on rotary phones allowed the use of physical locking mechanisms to prevent unauthorized use. The lock could be integral to the phone itself or a separate device inserted through the finger hole nearest the finger stop to prevent the dial from rotating. Principal dial mechanisms in the United States In the United States, two principal dial mechanisms arose in the development labs of the largest