The OptiX OSN 1500A is a single-layer structure with 12 slots when the slots are not split; there are 14 slots after splitting. The slot distribution has a correspondence, including the correspondence between the outlet board slot and the processing board slot, and the correspondence between the pairwise slots.

The location of each slot in the OptiX OSN 1500A slot when it is not split is shown in Figure 1.

Figure 1 Slot allocation diagram of OptiX OSN 1500A device (before slot splitting)

OptiX OSN 1500A slots 12 and 13 support splitting into 2 small slots, as shown in Figure 2.

Figure 2 Slot allocation diagram of OptiX OSN 1500A device (after slot splitting)

OptiX OSN 1500A's single board slot allocation:

• Line, Master, Crossover and Clock Combined Board Slot: slot 4 to 5
• Business processing single board slots before slot splitting: slots 6 to 9, slots 12 to 13
• Business processing single board slots after slot splitting: slots 2 to 3, slots 6 to 9, slots 12 to 13
• Business board slot: slot 9 (can double as processing board slot)
• Auxiliary interface board slot: slot 10
• Power supply board slots: slots 1 and 11
• Fan slot: slot 20

Correspondence between outlet board slots and processing board slots

The correspondence between the OptiX OSN 1500B outlet board slots and processing board slots is shown in Table 1.

For OptiX OSN 1500B, slot 7 and slot 12, slot 8 and slot 13, and slot 6 and 11 are three sets of slots. The slots are described below:

• Slot 7 and slot 12 share the outlet board slot slot 15, so you cannot insert a single board with an outlet board at the same time.
• Slot 8 and slot 13 share slot 17, so it is not possible to insert a single board with an outlet board at the same time.
• Slot 6 and slot 11 share slot 15 and slot 17, so it is not possible to insert a single board with an outlet board at the same time.
  Description:

  Slot 6 and slot 11 are protection slots. slot 6 provides protection for slots 7 and 8, and slot 11 provides protection for slots 12 and 13. According to the TPS protection principle, slot 6 and slot 11 share the outlet board slots slot 15 and slot 17.

Correspondence of Pairwise Slots

A pair of slots is a pair of slots where overheads can be passed through the backplane bus. When a single board is inserted in a pair of slots, it can realize the automatic pass-through of overheads such as K bytes, D bytes, E1, etc., improve the performance of multiplexing segment inversion, and not affect the DCC communication, official telephone, and other functions of other network elements when the main control board of the network element is not in position. The correspondence of the pairwise slots is shown in Table 2.