An implantable lead configured to be coupled to an implantable pulse generator header having a first connector port and a second connector port, the first connector port including a plurality of axially-spaced first header contact elements arranged in a first configuration and the second connector port including a plurality of axially spaced second header contact elements arranged in a second configuration, the lead comprising: a flexible lead body having a proximal end, a distal end portion, and a plurality of conductor lumens extending axially within the lead body from the proximal end to the distal end portion; a plurality of conductor wires, each conductor wire extending within one of the conductor lumens in the lead body; a plurality of electrodes coupled to the lead body in the distal end portion thereof, each of the electrodes being electrically coupled to at least one of the plurality of conductor wires; and a terminal connector assembly coupled to the proximal end of the lead body, the terminal connector assembly sized to be inserted into and received by the connector port of the pulse generator header and including a plurality of axially spaced terminal ring elements each electrically coupled to at least one of the conductor wires, the terminal ring elements separated from one another by an electrically insulating material, the terminal ring elements each having an outer surface having a first portion and a second portion, the first portion being electrically conductive and the second portion being electrically non-conductive, wherein the plurality of ring elements are axially arranged such that: upon full insertion of the terminal connector assembly into the first connector port, the first portion of each of the plurality of terminal ring elements is axially aligned with a respective one of the first header contact elements, and upon full insertion of the terminal connector assembly into the second connector port, the second portion of each of the plurality of terminal ring elements is axially aligned with a respective one of the second header contact element and the first portion of each of the terminal ring elements is axially separated and electrically isolated from the respective one of the second header contact elements. a flexible lead body having a proximal end, a distal end portion, and a plurality of conductor lumens extending axially within the lead body from the proximal end to the distal end portion; a plurality of conductor wires, each conductor wire extending within one of the conductor lumens in the lead body; a plurality of electrodes coupled to the lead body in the distal end portion thereof, each of the electrodes being electrically coupled to at least one of the plurality of conductor wires; and a terminal connector assembly coupled to the proximal end of the lead body, the terminal connector assembly sized to be inserted into and received by the connector port of the pulse generator header and including a plurality of axially spaced terminal ring elements each electrically coupled to at least one of the conductor wires, the terminal ring elements separated from one another by an electrically insulating material, the terminal ring elements each having an outer surface having a first portion and a second portion, the first portion being electrically conductive and the second portion being electrically non-conductive, wherein the plurality of ring elements are axially arranged such that: upon full insertion of the terminal connector assembly into the first connector port, the first portion of each of the plurality of terminal ring elements is axially aligned with a respective one of the first header contact elements, and upon full insertion of the terminal connector assembly into the second connector port, the second portion of each of the plurality of terminal ring elements is axially aligned with a respective one of the second header contact element and the first portion of each of the terminal ring elements is axially separated and electrically isolated from the respective one of the second header contact elements. upon full insertion of the terminal connector assembly into the first connector port, the first portion of each of the plurality of terminal ring elements is axially aligned with a respective one of the first header contact elements, and upon full insertion of the terminal connector assembly into the second connector port, the second portion of each of the plurality of terminal ring elements is axially aligned with a respective one of the second header contact element and the first portion of each of the terminal ring elements is axially separated and electrically isolated from the respective one of the second header contact elements.