Sometimes it happens that this ASCII based semigraphic of ncurses based applications bring some garbage characters. This happens especially running “putty” on a Windows client connecting to a Linux box. Here an example with “iftop”

                   195Kb               391Kb              586Kb               781Kb          977Kb
mqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqq

To solve the problem one has to set the variable

NCURSES_NO_UTF8_ACS

For example with bash syntax

export NCURSES_NO_UTF8_ACS=1 ; iftop

and than it looks much better

                   195Kb               391Kb              586Kb               781Kb          977Kb
+------------------+-------------------+------------------+-------------------+-------------------