diff --git a/Documentation/isdn/README b/Documentation/isdn/README
index 7b17183e..81e73493 100644
--- a/Documentation/isdn/README
+++ b/Documentation/isdn/README
@@ -215,6 +215,9 @@ README for the ISDN-subsystem
                                           an incoming call happened (RING) and
                                           the remote party hung up before any
                                           local ATA was given.
+			    Bit 7:    0 = Don't show display messages from net
+                                      1 = Show display messages from net
+				          (S12 Bit 1 must be 0 too)      
              14   0         Layer-2 protocol:
                                       0 = X75/LAPB with I-frames
                                       1 = X75/LAPB with UI-frames