Abstract: A Test Access Matrix (TAM) system permits installation onto an existing connector block. The TAM system exhibits a configuration that permits installation on to telecommunications circuits at the connection point provided for installation of protection modules or other devices that are inserted into the telecommunications circuit. The installation can be accomplished either before new or after existing connector blocks are installed on a telecommunication cross connect frame, tie frame, or other support structure. The TAM system can be instructed to connect a two or four wire test bus to any of the individual telecommunications circuits that are connected to the connector block. The test bus can be connected to the individual communication circuits in either a bridging, break towards the distribution side of the local loop, break towards the telecommunications equipment, or an insertion into the line via a “make before break” sequence. The bus can be further redirected to multiple test or monitoring devices.