Using the RJ203A With the EM203A Module
The RJ203A can also be used in combination with the EM203A module. Connector pins of the EM203A are designed to mate with interface pads of the RJ203A. The EM203A module itself fits "under" the RJ203A and partially within the recess area provided by the RJ203A. This recess area is formed by a translucent housing of the RJ203A. When the EM203A is combined with the RJ203A, the status LEDs of the EM203A become positioned close to the translucent front wall of the RJ203As and remain visible through the front face of the RJ203A.
Additional information can be found in the Mechanical Dimensions: RJ203A+EM203A topic.