190 BELL SYSTEM TECHNICAL JOURNAL 



In setting up service and operating arrangements, it was nec- 

 essary to give consideration to different conditions which would 

 exist dependent upon the volume of business to be handled over 

 the transatlantic channel. We had to consider operating practices 

 which could be used satisfactorily either under conditions of high 

 load and possibly delayed service or of light load and fast service. 

 As a means of insuring service to as many users as possible in periods 

 of heavy business, agreement was reached that there should be a 

 12-minute limit on individual usage in case other calls were awaiting 

 assignment to the radio channel. So far, there has been no occasion 

 to enforce this limitation. The limitation of 12 minutes was adopted 

 instead of the usual 6-minute limitation common in British telephone 

 practice for the reason that due to the relatively long talk periods on 

 business of this kind, the 6-minute limitation would have resulted in 

 interfering with too large a proportion of these communications. 



One problem of interest involved in the transatlantic service was 

 that of fixing rates which allowed of satisfactory expression either in 

 terms of English pounds and shillings or in American dollars. For 

 this purpose, 4 shillings was considered the equivalent of an American 

 dollar. The rate from London to New York, for example, is £ 15 

 for 3 minutes and £ 5 for each additional minute. Our zone rate 

 steps of $3 for the initial period and $1 for each additional minute 

 were so set in order to allow of even dollar and even shilling quotations 

 for the zone charges. The rate from Cleveland, for example, which 

 is in our second zone, to London is $78 for 3 minutes and $26 for 

 each additional minute. The same rate quoted from London is £ 15: 

 12s. for 3 minutes and £5: 4s. for each additional minute. Rate 

 treatment of this kind was thought desirable, not only to allow of 

 easy expression of rates in either English or American money, but 

 also to avoid odd cents in our service charges. 



Another problem had to do with the fixing of the hours of service 

 so that the service would be most valuable and usable with due regard 

 to the five hours difference in time between New York and London. 

 At the time the service was opened, limitations on the use of the 

 Rugby sending station for telephone transmission made it possible to 

 keep the channel open only 4| hours during the day. The hours 

 from 8:30 A.M. to 1:00 P.M., New York time, which correspond 

 with 1 :30 to 6 o'clock, London time, were adopted as allowing the 

 maximum overlapping of the London and New York business day. 

 Later, it became possible to extend the hours of operation so that now 

 the service is available 10| hours— 7:30 A.M. to 6 P.M., New York 

 time, which is 12:30 to 11 P.M., London time. The fact that 



