A connector apparatus for a pressure sensing catheter having a pressure-compliant member is disclosed. A first complementary connector has an aligning portion and a charging portion, with the aligning portion having a cross-sectional area less than a cross-sectional area of the charging portion. A second complementary connector has a proximal coupler with an alignment section and a charging section wherein, the alignment section having a cross-sectional area complementary to the cross-sectional area of the aligning portion to receive the alignment portion therein, the charging section having a cross-sectional area complementary to receive the charging portion and a resilient member therein. The first complementary connector can displace a volume of fluid from the proximal coupler into the pressure compliant member when the alignment section receives the aligning portion, the charging section receives the charging portion, and the resilient member forms the fluid tight seal within the charging section.
