Abstract: Service node for use in a communications network for providing access to services available to callers using the network. The service node includes a plurality of peripheral devices, a switch for connecting the peripheral devices to external communication links of the communications network for receiving calls made by callers to access a service provided by the service node; a control processor operable to generate a scan pattern representative of a plurality of individual patterns of characters corresponding to respective service commands relating to service options available to a caller, wherein the caller may originate any of the service commands during a call, and a distributed processing system.