CLI is the number that is transmitted when a call is made to another party (for example, the number that appears when a person calls your mobile phone). Your telecommunications provider sets this number. When the CLI is set to ‘Anonymous’, you cannot use the Residential Tenancies Bond Authority (RTBA) Fax Facility. You should discuss the CLI being displayed with your telecommunications provider. Fax machines linked to a Private Automated Branch Exchange (PABX) may need to be programmed to allow the fax number to be shown, in order to use the RTBA Fax Facility for estate agents.