Q. Advantages of subscriber loops signalling?

(i) Information can be exchange between processors much more faster than when channel associated signalling is used.

(ii) As a result, a much wider repertoire of signals can be employed and this enables more services to be provided to customers.

(iii) Signals can be changed or added by software modification to provide new services.

(iv) There is no longer any requirement for line signalling equipments on each junction that results in a considerable cost saving.

(v) As there is no line signalling, junctions canbe used for calls from B to A in addition to calls from A to B. Both wayworking needs fewer circuits to carry the traffic than if separate groups of junctions are provided from A to B and from B to A.

(vi) Signals relating to a call can be transmitted when the call is in progress. This allows customers to alter connections after they have been set up. For instance a customer can transfer a call elsewhere, or request a third party to be connected in to an existing connection.