Inbound -> DIDs -> Choose your did.
In-Group Call Handle Method - If IN_GROUP is selected as the DID Route, then this is the call handling method used for these calls. CID will add a new lead record with every call using the CallerID as the phone number, CIDLOOKUP will attempt to lookup the phone number by the CallerID in the entire system, CIDLOOKUPRL will attempt to lookup the phone number by the CallerID in only one specified list, CIDLOOKUPRC will attempt to lookup the phone number by the CallerID in all of the lists that belong to the specified campaign, CLOSER is specified for VICIDIAL Closer calls, ANI will add a new lead record with every call using the ANI as the phone number, ANILOOKUP will attempt to lookup the phone number by the ANI in the entire system, ANILOOKUPRL will attempt to lookup the phone number by the ANI in only one specified list, XDIGITID will prompt the caller for an X digit code before the call will be put into the queue, VIDPROMPT will prompt the caller for their ID number and will create a new lead record with the CallerID as the phone number and the ID as the Vendor ID, VIDPROMPTLOOKUP will attempt to lookup the ID in the entire system, VIDPROMPTLOOKUPRL will attempt to lookup the vendor ID by the ID in only one specified list, VIDPROMPTLOOKUPRC will attempt to lookup the vendor ID by the ID in all of the lists that belong to the specified campaign. Default is CID. If a CIDLOOKUP method is used with ALT, it will search the alt_phone field for the phone number if no matches are found for the main phone number. If a CIDLOOKUP method is used with ADDR3, it will search the address3 field for the phone number if no matches are found for the main phone number and optionally the alt_phone field.
Setting In-Group Call Handle Method to "CIDLOOKUP" will allow the system to search your entire list of prior leads and find the lead if it already exists (based on the CallerID of the inbound call). Read the options to understand exactly how this works and what the options actually do. This is set to "CID" by default which does not do a lookup.
Beware: A "dropped" inbound call will change the status of that pre-existing lead to "DROP" which can be annoying if it was "SALE" and you use that value in reporting!