Dialogic 6.2 manual Using the overlaprcv feature L4L3mENABLEPROTOCOL, What is Overlap Receive?

Using the overlap_rcv feature of L4L3mENABLE_PROTOCOL

Table 14. Q.931 Message Comparison Table (Continued)

Q.931Message	BSMI Message(L4L3m)	BSMI Message (L3L4m)
RESTart ACKnowledge	nothing	nothing
SEGMENT	nothing	nothing
CONGestion CONtrol	nothing	nothing
INFOmation	INFO_REQUEST	INFO
NOTIFY	nothing	UNIVERSAL
STATus	nothing	STATUS_IND
STATus ENQuiry	nothing	nothing
FACILITY	UNIVERSAL	UNIVERSAL

Using the overlap_rcv feature of

L4L3mENABLE_PROTOCOL

What is Overlap Receive?

When an ISDN call is received from the Public Telephone Network, the caller information arrives in a Q.931 SETUP message. Typically, this SETUP message contains all the information necessary for the user to properly route, switch and/or complete the call: information about the type of call (voice, modem, data, and so on), caller ID information, and so on.

Overlap Receive mode occurs when the incoming SETUP message contains no CALLED party information, or incomplete CALLED party information. The CALLED party information is necessary to complete a circuit-switched call, because it identifies the complete number that the originator is dialing.

The ITU Q.931 Recommendation defines a SENDING_COMPLETE Information Element as an indicator of when a SETUP message has complete CALLED party number information. If a SETUP message is received and there is no SENDING_COMPLETE info element in the message, the user is expected to enter Overlap Receive mode.

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