The invention relates to a method for transmitting digital voice data packets between voice data inputs of a plurality of channels and a transmitter. The chamber is located within a drum that is coupled to a nib of the writing instrument. In the temperature control apparatus, the length of the connecting pipe 21 is made substantially equal to or slightly shorter than the spacing between the heat exchanger 11 and the passage block 16. Application packages may also be upgraded. The valve is then selectively operated in a third or open position to discharge the container as desired. The drive arm may be made of a pull-molded composite material having a relatively low modulus of elasticity and a relatively high elongation factor.