Overview 
This page contains a list of clarifications and bug-fixes related to the Second Feature Interaction Contest. The information published on this page is not part of the Call for Participations or Instructions of the Contest. 
  • 08/10/99: Basic Call Model: A billing_onhook message is missing in the transistion from state BC7 to BC1 (onhook, A, A, -). The correct set of messages should be:
      • (onhook, A,A, -) 
      (billing_stop, A, B, time) 
      (billing_onhook, A, A, time) 
      (o_disconnect, A, B, -)
  • 08/10/99: All transistions without triggering events do not consume time and happen without time delay. That is, no external events can occur in these states and hence such events are not handled.
  • 08/10/99: Call Forwarding Busy: The communication between the CFB and the Basic Call Model is not working correctly.  More precisely, in state BC5, the Basic Call software is expecting an (i_free, B, A, -) message. However, if the call is forwarded to D the Basic Call Software will receive a (i_free, D, A), which it not expects. In order to solve this issue the CFB feature had to be modified. A new signal pair (o_notify, A, B, C) and (i_notify, A, B, C) has been introduced. This notifies B that their call to A has been forwarded to C.
  • 15/10/99: Basic Call Model: If a user went onhook in BC5 the message (o_stop_alert,A,B,-) is sent to the call software at the terminating side of the call. However, if the terminating side is still in BC9 the message (i_stop_alert,A,B,-) is lost. It could only be handled in BC10. Strictly, this is correct as according to item 2, transitions without triggering events (BC9 to BC10 is one of these) do not consume time and happen without time delay. However, not being able to handle the signal in BC9 seems to cause some troubles to some people. Thus, the BCM was updated and it is now possible to handle the event in BC9. As a consequence, the event (i_busy,A,C,-) is now handled in BC1 as well. This is necessary if the dialed party is busy and the originating party goes onhook in BC5.

    • The new updated version of the BCM can be downloaded as a tiff-file or eps-file. 
  • 07/01/2000: Tones are stopped with the next event.
  • 07/01/2000: Call Waiting: There is no node in CW2 for Z to disconnect. A corresponding branch has been included in the model. Also the signal (connect, X, X, -) on the transition CW1 -> BC11 (and CW11 -> BC11) is not needed. However, it is missing on the transitions CW4-> to BC7 (and CW14 -> BC7). 
  • 07/01/2000: Three Way Calling: The transitions TC4 -> BC7, TC5 -> BC7 and TC14 -> BC11, TC15 -> BC11 create a tone on the users telephone. However, in state BC7 and BC11 of the Basic Call Model the users are talking to the other party. Hence the tones need to be stopped.
  • 07/01/2000: Reverse Charging. There was a typo in the feature specification. The new version can be downloaded as a gzipped tiff file.
  • 07/01/2000: Split Billing: There was a typo in the feature specification. The new version can be downloaded as a gzipped tiff file.
  • 07/01/2000: Ringback when Free: After checking the "Ringback List" the feature sets up a Basic Call. However, the feature need to care about the user going offhook to establish the returned call. 
  • 07/01/2000: Voice Mail: Some branches allowing the user to go onhook while the feature is active are missing. 
  • 07/01/2000: Call Forwarding on Busy: After the transitions CFB2 -> BC6, CFB2 -> BC8, CFB2 -> BC1 the variable B needs to be assigned D. Otherwise the Basic Call will listen to events from B and not D.
  • 21/01/2000: Call Waiting: CW2 to BC7 and CW12 to BC11 should have two output events, as well as the present input event. The new updated version can be downloaded here: part one as gzipped tiff file and part two as gzipped tiff file.
  • 21/01/2000: Three way Calling: Flashing should be allowed in TC4 and TC5 as well as TC14 and TC15. To allow for this new transitions have been included. An updated version of the feature can be downloaded here: part one as gzipped tiff file and part two as gzipped tiff file.
  • 21/01/2000: Ringback when Free: The state RB2 was used twice in the diagram. Also the setup of the ringback call had to be changed. The new version of the specification can be downloaded as a gzipped tiff file.
  • 21/01/2000: Voice Mail: Some billing_onhhok messages were omitted. Also the behaviour of the feature when the subscriber is busy while a second call triggers the feature is insufficiently defined. Due to the close deadline the specification of the feature has been changed that it cannot be activated anymore when the subscriber is busy. The new version can be downloaded as a gzipped tiff file.
The contest committee is happy to help with enquiries. Please contact us at fiw00-contest@eee.strath.ac.uk