This standard establishes criteria and procedures for evaluating the on-hook and off-hook Resistance and Impedance performance of analog telephones and terminals. The recommended on-hook requirements are written with a model of five (5) Customer Premise Equipment (CPE) attached to the Customer Interface (CI) and the minimum performance requirements are based on a model of three (3) CPE. The current document addresses requirements for narrowband (300 to 3400 Hz) telephones that have traditionally been connected to the public switched telephone network (PSTN). Many of these telephones are now being connected to analog terminal adapters (ATAs) and voice gateways (VGs) for use with VoIP services. In some cases the telephones and the ATAs and VGs to which they are attached are capable of providing wideband (typically 150 to 6800 Hz) transmission performance. This revision will extend the on-hook and off-hook impedance requirements to cover the wider bandwidth, where appropriate, to ensure proper stability and echo control.