632 BELL SYSTEM TECHNICAL JOURNAL 



herent difficulties of, moving an automatically operated basket of 

 typebars back and forth in front of the stationary paper. The present 

 standard No. 15 teletypewriter was the ultimate result of this work 

 and has proved very satisfactory in general service over a number of 

 years. It employs a typewriter ribbon for inking, has the paper roll 

 inside the machine cover and makes very satisfactory carbon copies 

 with various types of paper supply without being subject to the paper 

 feed, inking and side print troubles previously experienced. 



This machine has also lent itself to meeting later demands from 

 business houses for typing either single or duplicate copies on special 

 printed forms as commonly used in modern business practice. By 

 equipping the platen with sprocket teeth and having feeding perfora- 

 tions along the edges of the forms, all copies of these forms are auto- 

 matically held in perfect registration during typing at all stations 

 connected to the circuit. In connection with the rapid handling of 

 these forms a further requirement for automatic tabulation has been 

 met by providing a tabulating device which on the transmission of a 

 certain signal causes all carriages to move over rapidly to any pre- 

 determined position on the form and stop there for the typing of letters 

 or figures in columns perfectly aligned. This device greatly facilitates 

 the rapid transmission and reproduction of orders and the like on 

 organized printed forms. 



With the advent of TWX service a new situation arose in which many 

 of the machines were only infrequently used and then for very short 

 periods to make a single copy only. To render this service economi- 

 cally it seemed desirable to have a less expensive machine and since 

 narrower capabilities were required this seemed entirely feasible. 

 Accordingly a new machine known as the No. 26 teletypewriter has 

 been developed primarily to print a single satisfactory copy although 

 one carbon copy can be made if desired. To obtain low first cost this 

 machine has a moving paper carriage and to secure a satisfactory 

 printed record it employs ribbon inking and a typewheel arrangement 

 which is a sort of cross between conventional typebar and typewheel 

 designs. This typewheel is an assembly employing a small individual 

 type pallet for each separate character. In the process of printing a 

 character, a striking arm somewhat like the shank of a typebar comes 

 forward and forces the individual type pallet against the ribbon to 

 make an impression on the paper. The typewheel is rotated to 

 different positions to select the different characters to be typed. In 

 this way satisfactory inking and a clear cut impression without side 

 print is obtained, which compares favorably with the record obtained 



