I have some suggestions/corrections to submit regarding H.450.4. Perhaps you would be kind enough to forward this to the appropriate department as necessary?
I\'ll start with a very minor suggestion:
1) It might be better to title section 11 as \"Dynamic description for call hold\" because sub-section 11.1.1 covers \"Near-end call hold\" and 11.1.2 covers \"Remote-end call hold\", thus section 11 covers both near-end and remote-end call hold.
2) If a new state called \"Hold_RE_Holding\" were introduced, this could simplify a state machine\'s implementation because it would prevent a held User retrieving the held call because the remoteRetrieve.req would then only be accepted when in the Hold_RE_Holding state. Thus only the served user would be able to retrieve the call.
3) Figure 18a refers to state Hold_RE_Held at the holding side and shows that if the served endpoint sends a remoteHold.req primitive then the state changes to Hold_RE_Retrieve_Req even though call retrieval has not been requested! I would have anticipated that the state would remain unchanged and so the state machine would still be waiting to receive a valid remoteRetrieve.req primitive.
4) Figure 18b in the central branch receives a remoteRetrieve.rr message. (This eventuality is already covered by the left hand branch.) It ought to say \"remoteRetrieve.re\" for a Return Error APDU.

Yours faithfully,
Neil Seymour