A press-fit circuit board connector comprising: a housing having a mating end and a mounting end opposite the mating end configured to be mounted to a host circuit board , the housing having a cavity between the mating end and the mounting end ; a mating contact assembly having a mating contact holder including a plurality of contact channels and a plurality of mating contacts received in corresponding contact channels , the mating contacts having mating pins at mating ends of the mating contacts , the mating contact assembly received in the cavity of the housing positioning the mating pins at the mating end to define a pin mating interface for mating with an electrical connector; and a mounting contact assembly having an interposer circuit board and a plurality of mounting contacts electrically connected to the interposer circuit board at corresponding circuits of the interposer circuit board , the mating contacts being electrically connected to corresponding circuits of the interposer circuit board to electrically connect the mating contacts and the mounting contacts via the interposer circuit board , the mounting contacts having press-fit mounting pins at mounting ends of the mounting contacts , the interposer circuit board received in the cavity with the press-fit mounting pins of the mounting contacts arranged at the mounting end for press-fit termination to the host circuit board , characterised in that the interposer circuit board includes a rigid upper circuit board , a rigid lower circuit board and a flexible circuit between the upper circuit board and the lower circuit board , the mounting contacts being electrically connected to the lower circuit board , the mating contacts being electrically connected to the upper circuit board , the flexible circuit electrically connecting the mating contacts electrically connected to the upper circuit board with corresponding mounting contacts electrically connected to the lower circuit board . a housing having a mating end and a mounting end opposite the mating end configured to be mounted to a host circuit board , the housing having a cavity between the mating end and the mounting end ; a mating contact assembly having a mating contact holder including a plurality of contact channels and a plurality of mating contacts received in corresponding contact channels , the mating contacts having mating pins at mating ends of the mating contacts , the mating contact assembly received in the cavity of the housing positioning the mating pins at the mating end to define a pin mating interface for mating with an electrical connector; and a mounting contact assembly having an interposer circuit board and a plurality of mounting contacts electrically connected to the interposer circuit board at corresponding circuits of the interposer circuit board , the mating contacts being electrically connected to corresponding circuits of the interposer circuit board to electrically connect the mating contacts and the mounting contacts via the interposer circuit board , the mounting contacts having press-fit mounting pins at mounting ends of the mounting contacts , the interposer circuit board received in the cavity with the press-fit mounting pins of the mounting contacts arranged at the mounting end for press-fit termination to the host circuit board , characterised in that the interposer circuit board includes a rigid upper circuit board , a rigid lower circuit board and a flexible circuit between the upper circuit board and the lower circuit board , the mounting contacts being electrically connected to the lower circuit board , the mating contacts being electrically connected to the upper circuit board , the flexible circuit electrically connecting the mating contacts electrically connected to the upper circuit board with corresponding mounting contacts electrically connected to the lower circuit board . <EOS>