punch and reader Model 38 = similar to Model 33, but for 132 char./line paper (14 inches wide), optional tape punch and reader Model 40 = new system processor based, w/ monitor screen, but mechanical "chain printer" Model 42 = new cheap production Baudot machine to replace Model 28 and Model 32, paper tape acc. Model 43 = same but for 8 level ASCII-plus-parity-bit, to replace Model 33 and Model 35, paper tape acc. Several different high-speed printers like the "Ink-tronic" etc. Texas Instruments Texas Instruments developed its own line of teletypes in 1971, the Silent 700. Their name came from the use of a thermal printer head to emit copy, making them substantially quieter than contemporary teletypes using impact printing, and some such as the 1975 Model 745 and 1983 Model 707 were even small enough to be sold as portable units. Certain models came with acoustic couplers and some had internal storage, initially cassette tape in the 1973 Models 732/733 ASR and later bubble memory in the 1977 Models 763/765, the first and one of the few commercial products to use the technology. In these units their storage capability essentially acted as a form of punched tape. The last Silent 700 was the 1987 700/1200 BPS, which was sold into the early 1990s. Telex A global teleprinter network called Telex was developed in the late 1920s, and was used through most of the 20th century for business communications. The main difference from a standard teleprinter is that Telex includes a switched routing network, originally based on pulse-telephone dialing, which in the United States was provided by Western Union. AT&T developed a competing network called "TWX" which initially also used rotary dialing and Baudot code, carried to the customer premises as pulses of DC on a metallic copper pair. TWX later added a second ASCII-based service using Bell 103 type modems served over lines whose physical interface was identical to regular telephone lines. In many cases, the TWX service was provided by the same telephone central office that handled voice calls, using class of service to prevent POTS customers from connecting to TWX customers. Telex is still in use in some countries for certain applications such as shipping, news, weather reporting and military command. Many business applications have moved to the Internet as most countries have discontinued telex/TWX services. Teletypesetter In addition to the 5-bit Baudot code and the