The first step in a phone system analysis is to determine if the jail is currently under contract with a vendor, and if so, the restraints of the contract. Jail officials should then independently determine what is required of an inmate phone system. Features to consider are a number-blocking system to prevent inmates from calling prohibited numbers, a listing of all outside phone numbers called by inmate personal identification number, a listing of all phone numbers within the facility called by each inmate, statistics on the number of calls, a listing of the most frequently called numbers, a limitation on the duration of inmate calls, automatic termination of efforts at three-way calling, and user-friendly features. A commission base should be negotiated from total gross revenues rather than net revenues. The jail administrator should survey existing commission rates throughout the industry to determine prevailing norms. When selecting a phone vendor either directly or through the local phone company, the vendor should be aware of the type of phone lines coming into the facility. The vendor should state in writing that the system proposed will work with the available service. The phone system should be comparable with the long-distance provider.