APPENDIX II
                                (to Recommendation X.224)
                                
  Differences between Recommendation X.224 and ISO 8073 (1986)
                                

       Recommendation X.224 and ISO 8073 (1986) are technically aligned except for 
the differences listed below:

II.1   Defect reports

       In collaboration, ISO and CCITT have agreed to corrections resulting from 
defect reports. Recommendation X.224 includes corrections from Reports 4, 6, 7, 9, 
11, 16, 17, 20, 22, 23, 27, 28, 29 (items 1-7), 32, 33, 34, 35, 36, 38, 39 (item 2), 
40, 41, 42, 43, 45, 52, 56, 59, 61, 65, 67, 69, 71, 72, 73, 74 (items 1-3 and 5-10), 
77 (item 2), 80, 81, 85, 89, 91, 93, 94, 103 and 106.  An update of ISO 8073 had not 
yet been published by March 1988.

Note - Defect Reports 1, 2, 3, 5, 10, 12, 13, 14, 15, 18, 19, 21, 25, 26, 51, 57, 
58, 60, 66, 74 (items 4, 11 and 12), 82, 84, 87, 88, 90, 92, 95, and 107 do  not
apply to Recommendation X.224 and in addition Defect Reports 8, 24, 29 (item 2), 39 
(item 1), 46, 48, 55, 62, 64 (item 2), 68, 76 (item 2), 77 (item 1), 79, 86, 97, 99 
and 104 have been rejected. No further changes to Recommendation X.224 will be made 
as a result of these defect reports.

II.2   Conformance

       Recommendation X.224, in section 14, requires all  systems  to  implement
class 0. ISO 8073, in Clause  14,  requires  all  systems  to  implement  either
class 0 or class 2.

II.3   Class negotiation

       An additional restriction regarding the classes of transport protocol that 
are proposed in a  CRTPDU  is  defined  in  item  (a)  in  sub-section  14.4  of
Recommendation X.224. No such restriction is contained in ISO 8073.

II.4   Precedence

       ISO 8073, in its Annex A (  ), includes the statement: "In the event of a 
discrepancy between the description in these tables and that contained in the text, 
the text takes precedence." Recommendation X.224 does not contain this statement.

II.5   Assignment to network connections

       In section 6.1.3 of Recommendation X.224 it is stated that the responder to 
the transport connect request becomes aware of the assignment when  it  receives
particular TPDUs. In Clause 6.1.3 of ISO 8073 it is the non-owner of the network 
connection that becomes aware of the assignment upon receipt of these same TPDUs.

II.6   Transport protocol identification

       The material contained in Annex B of Recommendation X.224 is not present in 
ISO 8073.

II.7   Checksum algorithms

       The material contained in Appendix I to Recommendation X.224 is contained in 











Annex B to ISO 8073.

II.8   Differences between Recommendation X.224 and ISO 8073

       The material in this appendix is not present in ISO 8073.