Collection of data on telephone interference factor

In a paper entitled, “Review of the Work of the Sub-committee on Wave Shape Standard of the Standards Committee,” which appeared in the January PROCEEDINGS, an account is given of work which has led to the adoption of three new standardization rules regarding wave shape, standardization rules No. 407, 408 and 409. Rule No. 407 defines the telephone interference factor of a wave and rule No. 408 gives the physical basis for its evaluation. Rule No. 409 reads as follows: