Dialogic M7324 Benutzerhandbuch

PBXs may use a method called in-band signaling to control their station sets. 
In-band signals use the same band of frequencies as the audio signal; this is 
usually accomplished with touch-tone signals. This method provides a limited 
amount of integration because there are no standards, and different PBXs provide 
varying levels of control. Call progress tones that even similar models send can 
vary. This means that applications, even on identical PBXs, would have to be 
tuned with each installation.  

An example of in-band signaling is transferring a call using the flashhook method 
There is no data (e.g., caller ID information) passed along when the call is 
transferred. 

Many PBXs use a method called out-of-band signaling to control their station 
sets. Out-of-band signals do not use the band of frequencies used by the voice 
signals. These PBXs transmit control signals and data that can include 
information such as called/calling number ID. Because of its versatility, out-of-
band signaling is often the selected method. 

Many PBX station sets have an LCD or LED screen that can display messages. 
The type of information that is displayed varies with the PBX manufacturer and 
the programming capabilities of the switch. Typical information includes: 
calling/ called number ID from within the switch, ANI digits from the CO, hook 
state, time and length of call, name assigned to the extension, and message 
waiting notification. With a Dialogic

® 

PBX Integration Board, this information 

can be passed “unprocessed” to the application. This means that the same data 
that is sent to the display is captured by the PBX Integration Board.  

By capturing the same display messages that a phone set receives, an application 
can “see” and “record” the display information. This display information (in 
ASCII format) can be useful in CT applications because it enables an application 
to know the state of the extension connected to the PBX Integration Board.