diff --git a/drivers/isdn/mISDN/Kconfig b/drivers/isdn/mISDN/Kconfig
index 6a97e86..4938355 100644
--- a/drivers/isdn/mISDN/Kconfig
+++ b/drivers/isdn/mISDN/Kconfig
@@ -23,5 +23,22 @@
 	  and get more informations about this module and it's usage.
 	  If unsure, say 'N'.
 
-	source "drivers/isdn/hardware/mISDN/Kconfig"
+config MISDN_L1OIP
+	tristate "ISDN over IP tunnel"
+	depends on MISDN
+	help
+	  Enable support for ISDN over IP tunnel.
+
+	  It features:
+	    - dynamic IP exchange, if one or both peers have dynamic IPs
+	    - BRI (S0) and PRI (S2M) interface
+	    - layer 1 control via network keepalive frames
+	    - direct tunneling of physical interface via IP
+
+	  NOTE: This protocol is called 'Layer 1 over IP' and is not
+	  compatible with ISDNoIP (Agfeo) or TDMoIP. Protocol description is
+	  provided in the source code.
+
+source "drivers/isdn/hardware/mISDN/Kconfig"
+
 endif #MISDN