trx: Add Hardware device support section

Change-Id: I87fc54cf1751f31a3e92d6503625e984f9a6130f
diff --git a/doc/manuals/osmotrx-usermanual.adoc b/doc/manuals/osmotrx-usermanual.adoc
index f2ccbaf..7d04f78 100644
--- a/doc/manuals/osmotrx-usermanual.adoc
+++ b/doc/manuals/osmotrx-usermanual.adoc
@@ -25,6 +25,8 @@
 
 include::chapters/trx-architectures.adoc[]
 
+include::chapters/trx-backends.adoc[]
+
 include::../common/chapters/trx_if.adoc[]
 
 include::../common/chapters/port_numbers.adoc[]