TIME INTERVALS IN TELEPHONIC CONVERSATION 287 



A few samples from the original oscillograms are shown in Fig. 2. 

 The speech energy in each sample is shown on traces 3 and 4 counting 

 from the top down, the upper being from Chicago and the lower from 

 New York. The cyclic waves on traces 2, 5 and 6 indicate respectively 

 lockout, establishment by Chicago and establishment by New York } 

 These waves were obtained from an oscillator which was concurrently 

 used to drive an escapement-type electric clock for measuring the total 

 call duration. 



The top oscillogram was selected to show the simplest type of con- 

 versational interchange. It will be seen that New York had been talk- 

 ing but had reached the end of his talkspurt as marked on the film. 

 Approximately 0.4 second later Chicago responded, his talkspurt ap- 

 parently consisting of three syllables, whereupon after a further time of 

 about 0.35 second New York responded and continued talking. The 

 second film was selected to show a less simple type of interchange where- 

 in a long pause within a talkspurt prompted the listener to reply. In 

 this instance the times were such that a lockout resulted. Since the 

 remainder of the talkspurt by the original talker, Chicago, was short 

 and the responding party. New York, continued talking, the circuit 

 was established in New York's direction after the lockout. In the 

 third oscillographic strip Chicago attempted to interrupt, and a short 

 pause by New York permitted lockout to occur; Chicago did not gain 

 control of the circuit. This is an example of concurrent talkspurts, 

 both of which were included in the data. The fourth example was 

 chosen to illustrate a negative response time. In this case Chicago 

 began to reply before the end of New York's talkspurt; no lockout 

 occurred, but the first part of the reply was inaudible to New York clue 

 to continued establishment of the circuit in the opposite direction. 



It may be noted in Fig. 1 that speech from Chicago was recorded 0.25 

 second before it was heard by New York and that speech from New 

 York was recorded 0.193 second before it arrived at Chicago. Likewise 

 the beginning of each response did not occur at the time shown on the 

 oscillograms but at a time previous by the delay from the talker's 

 position to that of the recording means. To obtain the response times 

 as previously defined each apparent response time was given an ap- 

 propriate time correction. 



Data Obtained 



The more detailed observations were made on fifty-one calls with a 

 total recorded duration of a little over 13,000 seconds. At the record- 

 ing speed of 20 feet per minute this resulted in about 4400 feet of 



* An establishment by a talker is said to occur when his speech energy has gained 

 control of all voice operated equipment in his transmission path. 



