chan configure, a built-in Tcl command, sets and retrieves options for channels. It replaces the older fconfigure.
Instruct Tcl to always send output to stdout immediately, whether or not it is to a terminal:
chan configure stdout -buffering none
Instruct Tcl to read pure bytes from a channel and write bytes to it, rather than characters:
chan configure $binaryDataFile -translation binary
The real name of the binary encoding is iso8859-1. -encoding binary was introduced as a migration aid to help with either the 7.6 -> 8.0 or the 8.0 to 8.1 transitions.
iso8859-1 has the privileged relationship with Unicode that its code-points are in a one-to-one relationship with \u0000-\u007f
Caveat: -encoding binary turns off -translation, but -encoding iso8859-1 does not.
RS 2015-04-13 - On Windows 7, stdout (if not redirected) breaks in a funny way when the encoding is changed - notice the "%" prompt:
D:\>Tcl85\bin\tclsh % fconfigure stdout -encoding utf-8 ‥ ‥^C D:\>Tcl86\bin\tclsh % fconfigure stdout -encoding utf-8 ‥exit
With longer output, the whole console (cmd.exe or Cygwin bash) freezes and can only be closed, but no longer be used.
This behavior was not the case in Tcl 8.4:
D:\>Tcl84\bin\tclsh % fconfigure stdout -encoding utf-8 %
LV 2008 Feb 28:
Some of the wiki pages talk about the construct,
chan configure $serial_port -mode "$baudRate,$plex,$bits,$polarity"
or some such thing. The -mode flag, used for specifying baud rate, etc, has moved to open now. I don't know how one would change those values on an open descriptor...