What is the function of expended card.how many band width of mux 3600 single shelf,doul shelf.27LC car...

You mean Expander Card.
The original chassis was fitted with only 6 slots and thus the control card can only manage these 6 slot single bandwidth. (2Meg per slot). As the 8 slot chassis was develop it was I think cheaper to build a new card as to build a new control card to manage the other two slot (7 and 8). So the expander card was build and to extend the shelf to 16 slots you do need the expander card fitted with a +16 expander module so that you can manage both chassis and provide double bandwidth per slot (4 Meg per slot).

There are two types of DNIC cards, nl. 6 circuit and 12 circuit. This card must be fitted with a DSP module if you want to configure the ports for 128K. Only 26XX DTU’s will work with this card. This card and DTU’s has been discontinued.

The 27LC2 card is a 6 circuit card and only 27XX and 2751/2/3 DTU’s will work with this card. This card and DTU’s has been discontinued.

The replacement for this card is the 27LC3 card and 27XX and 2751/2/3 DTU’s will work on them.

The 3600 mux is a single shelf which can be extended to a dual shelf. Each slot using a expander+16 can deliver 4 Meg. If only a single shelf is used you can fit a +8 module on the control card to provide you with 8 slots and 4 meg per slot.