Support of X.29 & TS29 in the YB/CONS Converter

1. It is necessary to support the relevant matrix of conversions in the converter.

2. It is not always necessary to route X.29/X.29 calls through the converter
   and should not be done so if at all possible to reduce the load on the
   converters.

3. The critical distinction is whether the source and destination of a call are
   in the same subnetwork.  If they are on different subnetworks, eg one on a
   Pink Book Ethernet and the other on a wide area subnetwork, then the converter
   MUST be used to overcome the lack of addressing information.

3. If they are both on the same subnetwork, ie a terminal/host using X.25 (1980)
   on the same wide area subnetwork as a terminal/host using X.25(1984), then
   by only using 1980 compatible features, it is possible to make a direct call
   from one to the other.  If it is the 1980 PAD making an X.29 call then it
   cannot use any new features and the call will succede.  If a PAD using X.29
   (1980) and X.25(1984) makes the call, the call can be made direct if only
   1980 features are used.

4. All TS29 calls must be converted.

Brian Gilmore
24th Nov. 1987