A multiswitch takes the input from both of the LNBs (both cables from a dual LNB dish HAVE to be connected to the multiswitch) and then locks one of the LNBs to always look at the even transponders and the other LNB to always look at the odd transponders. This is why a multiswitch only works with Dual LNBs and not single LNBs. The switch then has multiple outputs to receivers (4, 8 etc.). When you connect the receiver to the multiswitch, the switch determines which of the two LNBs the receiver needs to look at depending on whether it needs to view odd or even transponders. When you change the channel, the switch then swaps your connection to the other LNB if needed. With a multiswitch, the LNBs never change which side they are looking at.