ZyXEL Communications ACCESSING INTERNET & INTRANET omni series - Manual (Page 91)

Advanced ISDN Call Control 79
12
Advanced ISDN Call
Control
Call Control for DSS1
In order to initiate a DSS1 ISDN call, two information elements are
necessary:
•
Bearer Capability - indicates what kind of bearer service is
desired. It is also used for compatibility checking in the addressed
entity.
•
Called Party Number - provides necessary information for the
telephone company Central Office (CO) to direct the call to the
destination.
Other optional information elements which are pertinent to call
control include:
•
High-Layer-Compatibility.
•
Low-Layer-Compatibility.
•
Calling-Party-Number.
•
Called-Party-Number.
•
Calling-Party-Subaddress.
•
Called-Party-Subaddress.
Control of Outgoing Service Indicator
The High-Layer-Compatibility and Low-Layer-Compatibility
information provides a means for compatibility checking by the called
party. They are transferred transparently by the ISDN network
between the call originating entity (e.g. the calling user) and the
addressed entity.