RFC 856 (rfc856) - Page 1 of 4
Telnet Binary Transmission
Alternative Format: Original Text Document
Network Working Group J. Postel
Request for Comments: 856 J. Reynolds
ISI
Obsoletes: NIC 15389 May 1983
TELNET BINARY TRANSMISSION
This RFC specifies a standard for the ARPA Internet community. Hosts on
the ARPA Internet are expected to adopt and implement this standard.
1. Command Name and Code
TRANSMIT-BINARY 0
2. Command Meanings
IAC WILL TRANSMIT-BINARY
The sender of this command REQUESTS permission to begin
transmitting, or confirms that it will now begin transmitting
characters which are to be interpreted as 8 bits of binary data by
the receiver of the data.
IAC WON'T TRANSMIT-BINARY
If the connection is already being operated in binary transmission
mode, the sender of this command DEMANDS to begin transmitting
data characters which are to be interpreted as standard NVT ASCII
characters by the receiver of the data. If the connection is not
already being operated in binary transmission mode, the sender of
this command REFUSES to begin transmitting characters which are to
be interpreted as binary characters by the receiver of the data
(i.e., the sender of the data demands to continue transmitting
characters in its present mode).
A connection is being operated in binary transmission mode only
when one party has requested it and the other has acknowledged it.
IAC DO TRANSMIT-BINARY
The sender of this command REQUESTS that the sender of the data
start transmitting, or confirms that the sender of data is
expected to transmit, characters which are to be interpreted as 8
bits of binary data (i.e., by the party sending this command).
IAC DON'T TRANSMIT-BINARY
If the connection is already being operated in binary transmission
mode, the sender of this command DEMANDS that the sender of the
data start transmitting characters which are to be interpreted as
Postel & Reynolds