the origin of the text terminal and the command-line interface. Paper tape was sometimes used to prepare input for the computer session off line and to capture computer output. The popular Teletype Model 33 used 7-bit ASCII code (with an eighth parity bit) instead of Baudot. The common modem communications settings, Start/Stop Bits and Parity, stem from the Teletype era. In early operating systems such as Digital's RT-11, serial communication lines were often connected to teleprinters and were given device names starting with . This and similar conventions were adopted by many other operating systems. Unix and Unix-like operating systems use the prefix , for example , or (for pseudo-tty), such as , but some of them (e.g. Solaris & recent Linux) have replaced pty files by a pts folder (where "pt" stands for "pseudoterminal" instead). In many computing contexts, "TTY" has become the name for any text terminal, such as an external console device, a user dialing into the system on a modem on a serial port device, a printing or graphical computer terminal on a computer's serial port or the RS-232 port on a USB-to-RS-232 converter attached to a computer's USB port, or even a terminal emulator application in the window system using a pseudoterminal device. Teleprinters were also used to record fault printout and other information in some TXE telephone exchanges. Obsolescence of teleprinters Although printing news, messages, and other text at a distance is still universal, the dedicated teleprinter tied to a pair of leased copper wires was made functionally obsolete by the fax, personal computer, inkjet printer, email, and the Internet. In the 1980s, packet radio became the most common form of digital communications used in amateur radio. Soon, advanced multimode electronic interfaces such as the AEA PK-232 were developed, which could send and receive not only packet, but various other modulation types including Baudot. This made it possible for a home or laptop computer to replace teleprinters, saving money, complexity, space and the massive amount of paper which mechanical machines used. See also Letter-quality printer Plan 55-A, a message switching system for telegrams Radioteletype Siemens and Halske T52 – the Geheimfernschreiber (secrets teleprinter) References Further reading "Teletype Messages Sent Through Switch Board", Popular Mechanics, April 1932. AT&T offering two way service through switchboards on the role of the teleprinter code in WWII External links A first-hand report of Teletype Corporation's early years A Gallery