Practical application of telephone transmission calculations

I. General :¿General transmission equation ; standards ; graphical construction ; description of vector scale ; accuracy of graphical construction. II. Applications :¿Effect of terminal apparatus ; equivalents of various lines under different conditions ; reflection losses ; proposed new standard ; composite lines ; effect of direction of speaking ; allowances for apparatus in circuit. III. Experimental results :¿Predominant frequency of voice ; equivalent wave-form of voice ; speech tests on composite lines ; use of a single frequency for general testing ; tests on loaded lines ; tests on unloaded cable. IV. General conclusions. V. Appendix :¿Constants of telephone lines and apparatus.