diff --git a/scp.c b/scp.c
index 2b86191f..7627b016 100644
--- a/scp.c
+++ b/scp.c
@@ -1171,8 +1171,9 @@ static const char simh_help1[] =
       "5-a\n"
       " If the -a switch is specified, and the device being attached is a\n"
       " sequential output only device (like a line printer, paper tape punch,\n"
-      " etc.), the file being attached will be opened in append mode thus adding\n"
-      " to any existing file data beyond what may have already been there.\n"
+      " etc.), the file being attached will be opened for write and positioned\n"
+      " at the end of the file's current contents, thus adding to any existing\n"
+      " file data beyond what may have already been there.\n"
       "5-q\n"
       " If the -q switch is specified when creating a new file (-n) or opening one\n"
       " read only (-r), any messages announcing these facts will be suppressed.\n"