The base card has 8 ports built onto the card and can have an additional 2 modules installed each supporting 8 BRI connections bringing the capacity of a single card to 24 ports.

Figure 4.8 shows a side and front view of a BRI voice card with no modules installed with only the on board 8 ports. The additional modules can be installed in the locations indicated on the diagram. The second is connected into the centre bay (module 2) and the third module into the left hand bay (module 3).