A reduced-pressure system comprising: a dressing; a regulator (106, 200, 300, 1000) comprising: a supply chamber (204, 310, 1010) adapted to be fluidly coupled to the dressing, a charging chamber (208, 308, 1008) fluidly coupled to the supply chamber (204, 310, 1010) through a port, and a regulator valve (220, 326, 1026) coupled to the charging chamber (208, 308, 1008) and operable to reciprocate to control fluid communication through the port based on a differential between an ambient pressure and a therapy pressure; and a feedback interface fluidly coupled to the regulator (106, 200, 300,1000) and adapted to signal an operating state of the reduced-pressure system in response to a pressure received through the fluid coupling between the feedback interface and the regulator, characterised in that the feedback interface comprises a visual feedback interface, wherein: the feedback interface comprises a window (622, 830), a first indicator ring (614, 822), and a second indicator ring (616, 824); the first indicator ring (614, 822) is configured to be visible through the window (622, 830) at a first pressure; and the second indicator ring (616, 824) is configured to be visible through the window (622, 830) at a second pressure, wherein the feedback interface further comprises: a housing comprising a chamber disposed between an end wall and an open end, and the window (622, 830) is proximate to the open end; a diaphragm (604, 816) disposed in the chamber, the diaphragm (604, 816) having a peripheral portion coupled to the housing; a stem (610, 710) coupled to the diaphragm (604,816) and having a portion passing through the diaphragm (604, 816); a cap (612, 712) coupled to an end of the stem (610, 710) proximate to the open end of the housing, the cap (612, 712) having the first indicator ring and the second indicator ring; and a biasing member (606, 726) coupled between the diaphragm (604, 816) and the end wall, wherein the biasing member (606, 726) is adapted to exert a force urging the diaphragm (604, 816) toward the open end. a dressing; a regulator (106, 200, 300, 1000) comprising: a supply chamber (204, 310, 1010) adapted to be fluidly coupled to the dressing, a charging chamber (208, 308, 1008) fluidly coupled to the supply chamber (204, 310, 1010) through a port, and a supply chamber (204, 310, 1010) adapted to be fluidly coupled to the dressing, a charging chamber (208, 308, 1008) fluidly coupled to the supply chamber (204, 310, 1010) through a port, and a regulator valve (220, 326, 1026) coupled to the charging chamber (208, 308, 1008) and operable to reciprocate to control fluid communication through the port based on a differential between an ambient pressure and a therapy pressure; and a feedback interface fluidly coupled to the regulator (106, 200, 300,1000) and adapted to signal an operating state of the reduced-pressure system in response to a pressure received through the fluid coupling between the feedback interface and the regulator, characterised in that the feedback interface comprises a visual feedback interface, wherein: the feedback interface comprises a window (622, 830), a first indicator ring (614, 822), and a second indicator ring (616, 824); the first indicator ring (614, 822) is configured to be visible through the window (622, 830) at a first pressure; and the second indicator ring (616, 824) is configured to be visible through the window (622, 830) at a second pressure, wherein the feedback interface further comprises: a housing comprising a chamber disposed between an end wall and an open end, and the window (622, 830) is proximate to the open end; a diaphragm (604, 816) disposed in the chamber, the diaphragm (604, 816) having a peripheral portion coupled to the housing; a stem (610, 710) coupled to the diaphragm (604,816) and having a portion passing through the diaphragm (604, 816); a cap (612, 712) coupled to an end of the stem (610, 710) proximate to the open end of the housing, the cap (612, 712) having the first indicator ring and the second indicator ring; and a biasing member (606, 726) coupled between the diaphragm (604, 816) and the end wall, wherein the biasing member (606, 726) is adapted to exert a force urging the diaphragm (604, 816) toward the open end. the feedback interface comprises a window (622, 830), a first indicator ring (614, 822), and a second indicator ring (616, 824); the first indicator ring (614, 822) is configured to be visible through the window (622, 830) at a first pressure; and the second indicator ring (616, 824) is configured to be visible through the window (622, 830) at a second pressure, wherein the feedback