New T.35

Paul E. Jones paul.jones at
Mon Jun 28 10:31:28 EDT 1999


As many of you know, the latest T.35 document supports more than 254 country
codes.  In the newest document, T.35 says that one or two octets may be used
to indicate the country code.  If the first octet contains 1111 1111, the
second octet will contain the country code.

Unfortunately, the syntax in H.245 does not utilize extension markers, so
there is no place to hold second octet for the country code.  Therefore, I
would like to propose that, both for H.225.0 and H.245, we change the
comments in the ASN.1 from:

 t35CountryCode    INTEGER(0..255),   -- country, as per T.35
 t35Extension      INTEGER(0..255),   -- assigned nationally
 manufacturerCode  INTEGER(0..65535), -- assigned nationally

to the following

 t35CountryCode    INTEGER(0..255),   -- country, as per T.35 Annex A
 t35Extension      INTEGER(0..255),   -- assigned nationally, unless the
                                      -- t35CountryCode is 1111 1111, in
                                      -- which case this field shall
                                      -- contain the country code found
                                      -- in T.35 Annex B
 manufacturerCode  INTEGER(0..65535), -- assigned nationally

This may be a perversion of the t35Extension field, but we have a limited
number of options if we wish to support the usage of two octets for a
country code in H.245.

What are your opinions?

Best Regards,

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