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.
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...