A communication system including a fluid-operated calling device mounted in a first location in a building, and a fluid-operated indicator mounted in a second location in a building and in fluid communication with the fluid-operated calling device, wherein actuation of the fluid-operated calling device causes the fluid-operated indicator to provide an indication that the fluid-operated calling device has been actuated. A fluid-operated lock may be mounted near the fluid-operated calling device and in fluid communication with a fluid-operated actuator, wherein actuation of the fluid-operated actuator causes opening of the fluid-operated lock.