2 files changed, 19 insertions, 4 deletions

diff --git a/st.1 b/st.1
index b961b26..29e3163 100644
--- a/st.1
+++ b/st.1
@@ -89,9 +89,24 @@ embeds st within the window identified by
 .I windowid
 .TP
 .BI \-l " line"
-use a tty line instead of a pseudo terminal.
-When this flag is used
-remaining arguments are used as flags for stty.
+use a tty
+.I line
+instead of a pseudo terminal.
+.I line
+should be a (pseudo-)serial device (e.g. /dev/ttySO on Linux for serial port
+0).
+When this flag is given
+remaining arguments are used as flags for
+.BR stty(1).
+By default st initializes the serial line to 8 bits, no parity, 1 stop bit
+and a 38400 baud rate. The speed is set by appending it as last argument
+(e.g. 'st -l 115200'). Arguments before the last one are
+.BR stty(1)
+flags. If you want to set odd parity on 115200 baud use for example 'st -l
+parenb parodd 115200'. Set the number of bits by using for example 'st -l cs7
+115200'. See
+.BR stty(1)
+for more arguments and cases.
 .TP
 .B \-v
 prints version information to stderr, then exits.
diff --git a/st.c b/st.c
index d49804b..256f8f5 100644
--- a/st.c
+++ b/st.c
@@ -4294,7 +4294,7 @@ usage(void)
         "          [-i] [-t title] [-T title] [-w windowid] [-e command ...]"
         " [command ...]\n"
         "       st [-a] [-v] [-c class] [-f font] [-g geometry] [-o file]\n"
-        "          [-i] [-t title] [-T title] [-w windowid] [-l line]"
+        "          [-i] [-t title] [-T title] [-w windowid] -l line"
         " [stty_args ...]\n",
         argv0);
 }