Dialogic 6.2 manual Timing Diagrams, November 275

General Information

Timing Diagrams

To aid in the development process, timing diagrams that illustrate call setup and call teardown signaling in the various supported protocols are provided in the sections that follow. The diagrams consist of four parts:

„IISDN SMI Messages: Indicates the Bfv API messages sent to and received from the card during the call scenario.

„IISDN Timers: The timers possibly in use during the call scenario are listed, and active only during the periods on the diagram where the graph blocks are shaded.

„Receive and Transmit Signaling Bits: The thick black lines represent the signaling bits used to represent the call states in each protocol. Wink Start, Immediate Start/Fixed Pause and Delay protocols use only one bit (A-bit) to carry information, so only one line is shown for each direction. In these protocols, the value of the A-bit is seen as the “hook switch state” (“on hook” is low or zero, “off hook” is high or one). FXO/FXS Loop Start and Ground Start protocols use 2 signaling bits, A and B, to carry information, so two lines are shown for each direction. In these protocols, the bit values represent current feed and ring signal (FXO protocols), and hook state/ring current and ring ground (FXS protocols).

„Arrows and Vertical Dashed Lines: The arrows and vertical dashed lines indicate that there is a causal relationship between an event that occurs to the start of other events. For instance, the expiration of a timer can result in a change in the hook switch state, or a change in hook switch state can result in the start of a timer and issuance of an L3L4 message.

Note: The diagrams are designed to give the reader a general understanding of the sequence of events for various robbed bit protocols over time. The timers and spacing on the graphs are not proportional to the actual events that occur.

November 2009 275