Our biggest job of all came in 1923 when we changed over all the old Blue Code typewheel printers in the New York area to the new style L. C. Smith typebar printers using Green Code. (Morkrum bought L. C. Smith typewriters and added new machinery to them. Those printers became the famous Model 12.) As we have seen, a number of inventors had patented ways and means to adopt the five-unit code for operating a telegraph printer system by the transmission of a start pulse to start both transmitting apparatus and the distant receiving apparatus at the same time, followed by transmission of a selected code and a stop pulse. To achieve successful operation, very close speed adjustment was required. At first, this was achieved by the use of governed motors and, later, when accurately timed, 60-cycle alternating current became available, the problem of synchronous operation of send and receive stations was solved by the use of synchronous motors. [Illustration: Fig. 7 Morkrum Company’s Blue Code Typewheel Page Printer _Picture through courtesy of Teletype Corporation_] [Illustration: Fig. 7A Morkrum Company’s Green Code Typewheel Page Printer _Picture through courtesy of Teletype Corporation_] Telegraph printer systems of this type were used by telegraph companies for city-to-city transmission of telegrams and by news-gathering and -distributing organizations to transmit the news from headquarters to newspapers in different cities. While start-stop systems of this type were used successfully on press circuits and on telegraph message station-to-station circuitry, trouble was experienced when a number of printer send-receive units were set up in an intercommunicating system. Here it was found that the receiver start was not always in time with the transmitter start, due to varying line circuit conditions and a variation in the start release mechanism at connected stations. It seems odd that synchronous systems, where both transmitter and receiver were started at the same time (requiring both transmitter and receiver to maintain synchronism), held the field for so long a time, thus limiting telegraph transmission to one-way operation.