Abstract: There is disclosed a multifrequency tone distribution arrangement for a communication system having a common time division multiplexed bus in which digital samples of tone frequencies are supplied from a central signal generating circuit to system port circuits via selected time slots. Each port circuit automatically accepts selected signals from the common bus for conferencing to produce multifrequency digit tones and service tones.

Abstract: In time division communication systems one conference technique is to have a processor combine those samples going to a particular station forming a conference having as many subcombinations as there are stations. This approach, while allowing individual station gain adjustment, suffers from its dependence upon a large number of logic operations for a given conference. A modification of this technique is disclosed which uses a distributed structure such that the individual station ports, under local memory and processor control, operate to combine selected time slot samples into a conference sum unique to the station. In this manner gain values may be assigned on an individual listener station basis while the logic processing for the conference is performed in parallel by the ports involved in the conference.

Abstract: A central controller (104) for a multipoint polling system arranged to collect inquiry messages from data terminals (102a-n, 103a-n) for processing by a data base (101) and for distributing response messages to the terminals, the several terminals using different communication protocols. The controller includes a RAM memory (203) which stores a list of items, each item identifying a terminal and the type of protocol used thereby, a ROM memory (202) which stores an instruction set for each protocol type and a microprocessor (201) which sequentially accesses each item on the list to poll the associated terminal and accesses the instruction set identified in the item to control sending and receiving equipment to query and intercommunicate with the selected terminal in accordance with the accessed instructions.