Kabushiki Kaisha Toshiba

Nippon Telegraph and Telephone Corporation

Hirobumi Karasawa

Kunihiko Sekiya

Kensuke Uehara

Osamu Yamagishi

Satoru Hashimoto

Michiaki Okano

Tomoo Kunikyo

Shigeaki Tanimoto

Kazunori Iwasaki

Katsuhiko Kuma

Tadashi Kayano

Katsumi Nitta

A control unit transmits address area designation information designating an arbitrary bit position in ID data. At least a response unit transmits a response signal with an error detection code attached to predetermined information in the unique information held in itself by means of a time slot determined by the address area designation information and the ID data of the particular response unit. The control unit checks for the presence or absence of an error of the information in each time that has arrived, fetches only the response signal free of error, and transmits the error presence-absence information indicating the inspection result. Further, in the case where there exists a time slot having an error, the control unit transmits new address area designation information. In the case where an error exists in the time sot used previously by the response unit, the response unit retransmits the response signal in the time slot determined from the new address area designation information and the ID data of the response unit.

Information identification system for identifying response units by a

An improved time slot allocation method for a loop network. Loop networks in which the present invention is applied include a loop-connecting a control station and a number of branch stations. The control and branch stations each have at least one terminal connected thereto such that interstation communication, when demanded by a terminal, is made by passing a frame through the transmission path. The frame includes a synchronization area for indicating the leading end of the frame, a fixed-length control area, and a data area composed of a plurality of time slots. According to the invention, the control and branch stations are each allocated with a predetermined or unique number of time slots to be used by terminals for interstation communication. When a station has its reserve of unused time slots fall below a preset lower limit, the control station supplements time slots from its own reserve. On the other hand, if a station has its reserve exceed a preset upper limit, the station returns the excess time slots to the control station. Thus, wait times for a communication demand before a line connection is established are reduced, with enhanced control station response. Also, efficiency of time slot use is enhanced, with a considerable reduction in call losses.

Time slot allocation for loop networks

Growing community of inventors

Yokohama, Japan

Hirobumi Karasawa