Start-Stop Data Transmission Without the Stop Element

The existing start-stop telegraph system as used in the telex service allows for the transmission of 400 telegraph characters per minute when the CCIT recommended speed of 50 bauds is used. The signals comprise a start element and 5 information elements, each of unit length (20 msec), and a stop element with a duration of I 1/2 units, so that a telegraph signal of this type has a duration of 150 msec. This system allows for the transmission of 52 different letters and figures and six functionals, two of which are used for the change from letter shift to figure shift and vise versa. In this paper it is shown that it is possible to omit the stop element in a start-stop transmission of telegraph signals. This increases the telegraph speed from 400 characters per minute to 500 characters per minute. When special means are used and when it is possible to limit the the system to the transmission of numerical information, only a start element and four information elements are required. The telegraph speed will increase in that case to 600 characters per minute. This gain in speed may be exchanged for a parity check on the correct transmission. Various possibilities and their consequences are discussed in this paper.