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A program, similar to telnet, used to connect to remote IBM mainframe hosts, many of which do not understand telnet. The program emulates a 3270-type terminal.

For many tn3270 versions, the "clear screen" function is activated by typing Control-Z. When logged on to an IBM host and "HOLDING" or "MORE..." appears at the lower right corner of the screen, the "clear screen" function must be entered to display the next screen. tn3270 emulations usually include function key definitions.
This article is provided by FOLDOC - Free Online Dictionary of Computing (


(TelNet 3270) A client program that included the 3270 protocol for logging into IBM mainframes. Using the TCP/IP networking protocol, it was widely used to connect a desktop computer to a mainframe and emulate a mainframe terminal (3270) session.
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References in periodicals archive ?
None will likely have the TN3270, and many might not have the uncompression (or zip) package needed.
The Library of Congress ftp site houses text files about the Library's business and programs (and you don't need a tn3270 terminal to use it).
TN3270 provides "full-screen" access to mainframe applications and moves data rapidly from central databases onto the Macintosh and MS-DOS microcomputers.
"Until now, mainframe users have been struggling with integration challenges when trying to secure their FTP, TN3270, and other application connections between mainframes and Windows, Unix, and Linux systems," said Arto Vainio, CEO of SSH Communications Security.
The front-end user menu and all programs called from it (e.g., telnet, ftp, TN3270, WordPerfect.
This powerful tool simulates many industry protocols such as MATIP, IATA HTH, INT1, TN3270, AX25, Galileo TCD, SHARES UDP, SHARES TCP and many others -- at throughput rates of greater than 6,000 messages per second -- catering for the most complex of simulations.
Under the agreement, Cisco will provide its customers who purchase or have purchased a TN3270 server with 50 no-charge licenses of IBM's host integration software, Host On-Demand, which offers web access to applications and data that reside on host computers.
Developers and support staff at Apollo Travel Services, the network services arm of United Airlines, needed to access Galileo's 3270-based host applications and data via TN3270 emulation over the corporate WAN, and Galileo had only two weeks to bridge the gap between the two systems.
With this in mind, users should investigate which protocols and applications (e.g., Bin, CSO, MIME, WAIS, telnet, tn3270, and gateway access to the latest version of Z39.50 servers) are supported by the clients.