The CCITT, considering that phototelegraph calls are frequently set up on circuits normally used for telephone traffic; that the holding time of these circuits used depends not only on the duration of the phototelegraph transmission proper but also on the time needed to prepare the call and return the circuits used to the telephone service; that when a phototelegram is handled, the cost includes the handing in and delivery expenses as well as the cost of using public phototelegraph stations.