http://www.rfc-editor.org/rfc/rfc0946.txt
RFC 0946: Telnet terminal location number option, R. Nedved1985-05-01T23:00:00-00:00Many systems provide a mechanism for finding out where a user is logged in from usually including information about telephone extension and office occupants names. The information is useful for physically locating people and/or calling them on the phone. In 1982 CMU designed and implemented a terminal location database and modified existing network software to handle a 64-bit number called the Terminal Location Number (or TTYLOC). It now seems appropriate to incorporate this mechanism into the TCP-based network protocol family. The mechanism is not viewed as a replacement for the Terminal Location Telnet Option (SEND-LOCATION) but as a shorthand mechansim for communicating terminal location information between hosts in a localized community. This RFC proposes a new option for Telnet for the ARPA-Internet community, and requests discussion and suggestions for improvements.