ScopeIntended Audience: All End UsersThis article outlines how to configure a SIP Trunk between your hosted PBX and a 3CX PBX. This article was written using 3CX Version 18.0 Update 3 (Build 461)RequirementsSIP Trunk InformationExisting 3CX instanceConfigure SIP TrunkLog in to the 3CX PBX instanceClick SIP TrunksClick Add SIP TrunkSet the Country to GenericSet the Provider to Generic SIP TrunkEnter the 10-digit telephone number of your trunk, with no spaces or special characters in the Main Trunk NoClick OKIn the General tab, complete the following fields, leaving all others defaultName: Enter a descriptive name for the trunkRegistrar/Server/Gateway Hostname or IP: Enter the name of the SIP TrunkAuto Discovery: UncheckedOutbound Proxy: Enter the outbound proxy based on your primary core. If unsure, contact support.hosted.clearclouds.caNumber of SIM Calls: Set the number of simultaneous calls for the PBX you wish to allowType of Authentication: This will vary based on the kind of trunk you wish to configure. If an IP-based SIP trunk was set up initially, leave as Do not require - IP based. If an authentication-based trunk was configured, select Register/Account based Authentication ID (aka SIP User ID): Enter the SIP User ID from the SIP trunkNOTE: This is not needed if an IP-based trunk was configuredAuthentication Password: Enter the SIP User Password from the SIP trunkNOTE: This is not needed if an IP-based trunk was configuredDestination for calls during office hours: Choose where to route inbound calls during hoursDestination for calls outside office hours: Choose where to route calls outside office hoursDo not modify the outbound parametersClick OKOnce the trunk is registered, 3CX should show a green circle to the left of the trunk.For authentication-based trunks, the portal will then show the IP address of the registered trunkAdd Outbound RulesIn order to configure outbound calling through the SIP trunk, outbound rules will need to be added.Navigate to Outbound Rules Click AddSet a Rule NameSet Calls to Numbers with a length of to 10-11Set Route 1 to the newly created trunkClick OKTo configure international calling, click AddSet a Rule NameSet Calls to Numbers starting with prefix to 011Set Route 1 to the newly created trunkClick OKClick OK