diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 41b5d7144d..6419bee499 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -1793,7 +1793,13 @@ SystemCallErrorNumber=EPERM
systemd.socket5 for more
details about named file descriptors and their ordering.
- This setting defaults to .
+ This setting defaults to .
+
+ Note that services which specify and use
+ StandardInput= or StandardOutput= with
+ //, should specify
+ , to make sure that the tty intialization is
+ finished before they start.