diff --git a/doc/manuals/osmotrx-usermanual.adoc b/doc/manuals/osmotrx-usermanual.adoc
index 249a21c0..3b2e9917 100644
--- a/doc/manuals/osmotrx-usermanual.adoc
+++ b/doc/manuals/osmotrx-usermanual.adoc
@@ -23,6 +23,8 @@ include::chapters/counters.adoc[]
 
 include::chapters/configuration.adoc[]
 
+include::../common/chapters/trx_if.adoc[]
+
 include::../common/chapters/port_numbers.adoc[]
 
 include::../common/chapters/bibliography.adoc[]