Dialogic 6.2 Manuale Utente

General Information

November 2009

275

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.

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.