Abstract: A digital station line controller is connected via a digital link, such as a T1 span, to the line side of a central office and via digital station line loops to digital terminal devices, such as telephones. The station line controller interprets certain signals used by a conventional protocol, such as TR8, between a central office and a remote terminal, as status requests. In response to the status requests, the station line controller provides status information obtained by monitoring the terminal devices connected thereto and the station line controller itself. The status information may be obtained by generating codes which perform tests of the terminal devices and the station line controller. In addition, non-voice information transmitted over a subscriber channel in the on-hook, no-ring state of the subscriber channel is decoded and used or output by the station line controller to a corresponding terminal device or auxiliary equipment.

Abstract: In a communication network wherein a master station periodically polls a number of remote stations to determine whether or not each remote station has data to transmit to the master, each of the remote stations is assigned to one two groups. One of the groups is designated as priority stations which commonly have very urgent data for the master station. The group of non-priority stations is sequentially polled for messages to be sent to the master station. The polling of the group of non-priority stations is periodically interrupted so that the master station may poll each of the stations in the priority group to determine if they have messages to send. Upon the completion of the polling of the priority stations, the polling of the non-priority stations is resumed. Periodically a time period occurs for inactive stations to join one of the two groups of stations on the network.