Sorry,

In the meantime I found the H.225 section telling about basic aligned variant of X.691 to be used for H.225.0 User-user information element ASN.1 encoding.

The same of course shall apply for H.450 Supplementary service APDUs (which are carried in User-user information element)

Regards, Karl Klaghofer Siemens AG

---------- From: Klaghofer, Karl PN M BT Sent: Thursday, September 18, 1997 6:15 PM To: 'itu-sg16List' Subject: Octet-aligned encoding for H.450.x ? Importance: High

The H.450 Supplementary Services make use of the Packed Encoding Rules (PER) according to X.691 (inline with H.225, H.245).

X.691 specifies four encoding rules: BASIC-PER, CANONICAL-PER, both in two variants the ALIGNED variant, and the UNALIGNED variant.

Are all of these encodings mandatory in H.323 (H.225, H.245) to support ?

Should we limit the X.691 variants in H.450.x (clause 9 of H.450.1) to ALIGNED only ?

Regards, Karl Klaghofer Siemens AG karl.klaghofer@mch.pn.siemens.de