Thomas, did you have some specific reason for this minor inconsistency
with MIDI & RS232 options (having extra convenience option for setting
both input&output at same time, but only for SCC)?
I can't remember, but looking at the history, I first added the "--scc-b"
option (commit e2d62ee2f876a8) and then later the -out and -in options
(commit 300d3ee496980) - I assume it was initially not possible to use
separate file handles for input and output.
Anyway, I agree that it should be made consistent now with the other serial
options.