Telnet send-location option
A Telnet option that lets a user's Telnet program tell the server where the user is physically located.
Killian, E., "Telnet send-location option", RFC 779, DOI 10.17487/RFC0779, April 1981, <https://www.rfc-editor.org/info/rfc779>.
@misc{rfc779,
series = {Request for Comments},
number = 779,
howpublished = {RFC 779},
publisher = {RFC Editor},
doi = {10.17487/RFC0779},
url = {https://www.rfc-editor.org/info/rfc779},
author = {E. Killian},
title = {{Telnet send-location option}},
pagetotal = 2,
year = 1981,
month = apr,
} RFC text
Network Working Group E. Killian
Request for Comments: 779 LLL
April 1981
TELNET SEND-LOCATION Option
1. Command name and code.
SEND-LOCATION 23
2. Command meanings.
IAC WILL SEND-LOCATION
The sender REQUESTS or AGREES to use the SEND-LOCATION option to
send the user's location.
IAC WON'T SEND-LOCATION
The sender REFUSES to use the SEND-LOCATION option.
IAC DO SEND-LOCATION
The sender REQUESTS that, or AGREES to have, the other side use
SEND-LOCATION commands send the user's location.
IAC DON'T SEND-LOCATION
The sender DEMANDS the other side not use the SEND-LOCATION
option.
IAC SB SEND-LOCATION <location> IAC SE
The sender specifies the user's location to the other side via a
SEND-LOCATION subnegotiation. <location> is a sequence of ASCII
printable characters; it is terminated by the IAC SE.
3. Default.
WON'T SEND-LOCATION
DON'T SEND-LOCATION
TELNET SEND-LOCATION Option
4. Motivation for the option.
Many network sites now provide a listing of the users currently
logged in giving their names and locations (see the NAME/FINGER
protocol, RFC 742). The location is useful for physically locating
the user if he or she is nearby, or for calling them (a nearby phone
number is often included). However, for users logged in via the
network, the location printed is often no more than the originating
site name. This TELNET option allows the user's TELNET program to
send the user's location to the server TELNET so that it can be
displayed in addition to the site name. This functionality is
already present in the SUPDUP protocol (RFC 734).
5. Description of the option.
When the user TELNET program knows the user's location, it should
offer to transmit this information to the server TELNET by sending
IAC WILL SEND-LOCATION. If the server's system is able to make use
of this information (as can the ITS sites), then the server will
reply with IAC DO SEND-LOCATION. The user TELNET is then free to
send the location in a subnegotiation at any time.
AI ELI5
On this page
§1Why Send a Location
Many sites list users currently logged in with names and locations (see the NAME/FINGER protocol, RFC 742). The location helps physically find a user who is nearby or call them, since a nearby phone number is often included. For network users the location is often no more than the originating site name.
This option lets the user's Telnet program send the location to the server Telnet for display in addition to the site name. The same function is already in the SUPDUP protocol (RFC 734).
A list of who is online is more useful if it says which room they are in, not just which building.
§2Commands
The option is SEND-LOCATION with code 23. IAC WILL SEND-LOCATION requests or agrees to send the user's location. IAC DO SEND-LOCATION requests or agrees to have the other side send it. The WON'T and DON'T forms refuse or demand the other side not use the option. The default is WON'T and DON'T.
The location itself travels as IAC SB SEND-LOCATION <location> IAC SE, where the location is a sequence of ASCII printable characters terminated by the IAC SE.
One side offers, the other accepts, and then the location is sent as a short line of normal letters.
§3How It Is Used
When the user Telnet knows the user's location, it should offer to send it by sending IAC WILL SEND-LOCATION. If the server's system can make use of the information, as the ITS sites can, the server replies IAC DO SEND-LOCATION. The user Telnet is then free to send the location in a subnegotiation at any time.
Your computer asks 'want to know where I am?'. If the answer is yes, it can tell the location any time.