1-3Two Cabinet SystemWhen it is required that the basic system be expanded to provide a capacity greater than thatdescribed above, the Signal Control Processor (SCP) card must be installed in slot nine of the firstcabinet. This card provides an intermediate level of processing to control the first cabinet thereforefreeing resources on the Main Control Processor (MCP) to control the entire system. Adding the SCPcard therefore reduces the number of universal card slots in the first cabinet to eight. In addition, theMCP card must be equipped with a ESM daughter board and a IPM daughter board. Only a LANdaughter board may optionally occupy the remaining daughter board position on the MCP card. Allother types of daughter boards must be installed on the SCP card or LCP card.Adding one expansion cabinet makes the system a two cabinet system with 17 universal card slots(see Figure 1–2). This allows a maximum of 240 stations or 232 lines when using TEPRI cards.Without the TEPRI cards, the maximum number of lines is 136 while the maximum number of stationsremains at 240. This second cabinet is controlled by a Local Control Processor (LCP) in a similarmanner to the SCP in the first cabinet and connects to the MCP via a 25 pair cable. The LCPprocessor card resides in a dedicated slot 10 of the second cabinet and therefore does not deplete thenumber of universal card slots.NOTE: The first power supply slot in each cabinet must be occupied by a PSU-B to supply sufficientpower to all 10 slots (9 universal and a processor slot) and support up to 56 stations. The secondpower supply slot can be occupied by either a PSU60 or PSU-B. Do not use a PSU40 in either PSUslot.Figure 1–2 iDCS Two Cabinet System