Henri, To answer you question and to add to what Frank said, there is no semantic difference. The extension marker is just a syntactic mechanism for augmenting an ASN.1 tree. Paul Long Smith Micro Software, Inc. -----Original Message----- From: henri.maenpaa@NOKIA.COM [SMTP:henri.maenpaa@NOKIA.COM] Sent: Monday, March 22, 1999 1:49 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: basic ASN.1 coding question Hi everyone, I have a pretty basic/specific question about ASN.1 coding: what's the semantic difference if a particular information element is located above/below the "three dots"-line in an ASN.1 structure? -Henri Mäenpää