Using a combination of uniselectors and two motion selectors draw a schematic of thousand line exchanges.

The schematic diagram for such an exchange is demonstrated in Fig. All subscribers is connected to a single rotary pre-selector switch at the exchange, and the outputs from  this switch being linked to a bank of two-motion switches termed as 'group selectors'. The outputs from the pre-selector switches of an entire group of subscribers are connected together in parallel such as group of subscribers share a single bank of group selectors. If a subscriber lifts his telephone then the cradle switch causes a circuit to be completed reverse to the telephone exchange, signaling which the subscriber wants to make a call. It is causes the pre-selector switch to step around till it find a free group selector. The pre-selector switch then stops in such position and the group selector are 'seized' through the subscriber wishing to make a call.

FIG - 1000 Line Exchange