ZyXEL Communications Omni TA128 - Manual (Page 86)

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11
Advanced ISDN Call
Control
Call Control for DSS1 (Digital Subscriber
Signaling #1)
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