Cisco Systems TN093 2.2 DirectSIPIntegrationusingT.38RelaywithCNGDetection

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ObjectworldCommunicationsCorp.•308LeggetDrive•Ottawa,ON•Canada•K2K1Y6•613‐599‐9698•F:613‐599‐7457•www.objectworld.comT:
session protocol sipv2
session target ipv4:192.168.8.129
codec g711ulaw
!
dial-peer voice 2852 voip
description Incoming Fax Calls to UC Server
destination-pattern 71..
session protocol sipv2
session target ipv4:192.168.8.54
codec g711ulaw
fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback none
!
sip-ua
!
2.2 DirectSIPIntegrationusingT.38RelaywithCNGDetection
DirectSIPIntegrationusingT.38relaywithCNGdetectionallowsasingleincomingtelephonenumbertoreceivevoiceand
faxcalls.Allincomingcallswillbepre‐answeredtodetermineiftheincomingcallerisafaxmachinethatgeneratedCNG
tones.IfCNGtoneisnotdetected,thecallerwillbetransferredtotheassociateduser’sextensionoveraconfiguredSIP
trunkbetweenObjectworldUCServerandCiscoCallManager.Thepre‐answerservicerequiresthedatabaseintegration
featuretobeenabledonUCServerandfortheUCServeradministratortoassociateincomingDIDcallednumberstoan
internalextensiononCiscoCallManager.
InorderforaCiscoIOSgatewaytodetectCNGtonesanapplication(TCLapplicationscript)mustbeloadedontotheCisco
gateway.TCLisaCiscoIVRprogramminglanguage.TheTCLScriptthatwillperformtheCNGdetectiondoesthe
followinghighlevelfunctions.
1. DirectanincomingPOTScalltotheapplicationservice.
2. TheincomingcallisredirectedbytheCNG‐detectTCLscripttoavoicepre‐answeringservice.IfCNGtoneis
detectedthecalltothepre‐answeringserviceisterminatedandanothercallismadetothefaxansweringservice.
TheTCLscriptmodifiestheoriginalcallednumber(DNIS)byaddingsomeprecedingroutingdigitsinfrontofthe
originalcallednumberandthendirectsittoUCServerusingaSIPVoIPdialpeer.This���callisthenansweredbyUC
Serverbyanapplicationservicethatplaysaringbacksound(optionallyitcanbeconfiguredtoplayanaudio
prompt)forashortperiodoftime.Aftertheaudioisplayedtheservicewillthenperformablindtransfertothe
associatedCiscotelephoneextension.
3. IftheCiscoGatewaydetectsCNGtone,itwillteardowntheoriginalcallanddirectsthecalltoaSIPVoIPdialpeer
byinsertingsomeroutingdigitsinfrontoftheoriginalcallednumber.UCServerwillthenroutethecalltoauser’s
faxidentitythatisassociatedwithaUCServeruser.