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ntegrated Services Digital Network (ISDN) User Part (ISUP) [12] is a level 4 protocol used in Signaling System No. 7 (SS7) networks.

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Posted by waqasahmad

In short we define ISUP used to establish and maintain connections for voice and data calls

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Posted by HamidAliKhan

ISUP used to establish and maintain connections for voice and data calls

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Posted by Hash007

For details:

en.wikipedia.org/wiki/ISDN_User_Part

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Posted by sagitraz

ISUP is the ISDN User Part of SS7. ISUP defines the protocol and procedures used to setup, manage and release trunk circuits that carry voice and data calls over the public switched telephone network. ISUP is used for both ISDN and non-ISDN calls. Calls that originate and terminate at the same switch do not use ISUP signalling. ISDN User Part messages are carried on the signalling link by means of signal units. The signalling information field of each message signal unit contains an ISDN User Part message consisting of an integral number of octets.

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Posted by treyton