1-2-1 letter space 1-2-3 carriage return 1-2-4 line space 1-3-1 type wheel shift 1-3-2 type wheel release 1-3-4 A 1-4-1 I 1-4-2 O 1-4-3 D 2-1-2 E 2-1-3 H 2-1-4 N 2-3-1 W 2-3-2 R 2-3-4 S 2-4-1 T 2-4-2 V 2-4-3 U 3-1-2 - 3-1-3 , 3-1-4 ? 3-2-1 Y 3-2-3 C 3-2-4 F 3-4-1 G 3-4-2 Q 3-4-3 L 4-1-2 M 4-1-3 J 4-1-4 B 4-2-1 X 4-2-3 Z 4-2-4 . 4-3-1 K 4-3-2 P 4-3-4 The numerals in the above code or system indicate the sequence of the impulses through the relay contacts 1, 2, 3 and 4. Cardwell’s backers formed the American Telegraph Typewriter Company and sold shares, claiming a great profitable future for their apparatus. A few printers were built, but, on extended service tests, the high-low-voltage feature proved to be impractical and the company folded. J. C. Barclay of the Western Union Telegraph Company designed printing apparatus and perforated tape transmitting equipment for this type of system, but, after limited use of the high-low-voltage principle, he changed this feature to long and short pulses with discriminating relays. With later improvements, this system was put into service on a number of Western Union message circuits. _Note:_ Today, in the 1960s, the techniques of frequency division and electronics could be used for transmitting three different line conditions from a group of four different frequencies. In such a system, synchronism between send and receive terminals, or the start-stop method to control correct timing, is not needed. The transmission of any selected group of three, when received in succession at a teleprinter, will cause printing of a letter when the third receiving relay completes a circuit to the selected printing magnet. Transistor circuits with associated control elements could replace the relays. Telegraph companies in the United States were mostly using the Morse and increased its efficiency through development of quadruplex operation and high-speed transmission systems. However, the quest for a more efficient printing telegraph system persisted and various types were proposed and tried. All made use of codes that were impractical for intercommunicating systems and, while some were used in message service by the telegraph companies, they did not appear to have any great advantage over the Morse telegraph.