An apparatus to communicatively couple a field device to a remote terminal unit , the apparatus comprising: a base rack for said remote terminal unit in a process control system ; a first termination module to be inserted in a first termination slot (211-218) of the base rack , wherein the first termination module is configured to receive wires that are communicatively coupled to said field device ; and a first control module , separate from the first termination module , to be inserted in a first control slot of the base rack , wherein the first control module to be communicatively coupled with the first termination module via a first termination link that communicatively couples the first control slot to the first termination slot on a backplane of the base rack , wherein the first control module is configured to control communications with the field device , the apparatus is characterized in that : the first termination module includes a signal conditioning card connected between the first termination slot on the base rack and a terminal block , wherein the signal conditioning card includes a backplane connector to communicatively couple the first termination module to the backplane, wherein the terminal block includes termination points to terminate the wires from the field device , wherein the first control module is separable from the base rack without unwiring the wires from the termination points , wherein the terminal block is separable from the signal conditioning card without unwiring the wires from the termination points , and wherein the signal conditioning card is separable from the backplane without unwiring the wires from the termination points . a base rack for said remote terminal unit in a process control system ; a first termination module to be inserted in a first termination slot (211-218) of the base rack , wherein the first termination module is configured to receive wires that are communicatively coupled to said field device ; and a first control module , separate from the first termination module , to be inserted in a first control slot of the base rack , wherein the first control module to be communicatively coupled with the first termination module via a first termination link that communicatively couples the first control slot to the first termination slot on a backplane of the base rack , wherein the first control module is configured to control communications with the field device , the apparatus is characterized in that : the first termination module includes a signal conditioning card connected between the first termination slot on the base rack and a terminal block , wherein the signal conditioning card includes a backplane connector to communicatively couple the first termination module to the backplane, wherein the terminal block includes termination points to terminate the wires from the field device , wherein the first control module is separable from the base rack without unwiring the wires from the termination points , wherein the terminal block is separable from the signal conditioning card without unwiring the wires from the termination points , and wherein the signal conditioning card is separable from the backplane without unwiring the wires from the termination points . <EOS>