[54] DUPLICATE CONTROL AND PROCESSING UNIT FOR TELECOMMUNICATIONS EQUIPMENT
[75] Inventors: Carlo De Leva. Monza; Maurizio
Zambardi. Cassina De* Pecchi, both of
Italy
[73] Assignee: Siemens Telecommunicazioni S.p.A.. Milan, Italy
[21] Appl. No.: 411,686
[22] PCT Filed: Sep. 15, 1993
[86] PCT No.: PCT/EP93/92496
§371 Date: Mar. 30, 1995
§ 102(e) Date: Mar. 30,1995 [87] PCT Pub. No.: WO94/08292
PCT Pub. Date: Apr. 14,1994
[30] Foreign Application Priority Data
Sep. 30, 1992 PT] Italy MI92 A 002261
[51] Int CI.6 G06F 11/20
[52] U.S. CI 395/182.11
[58] Field of Search 395/182.11. 182.04
[56] References Cited
U.S. PATENT DOCUMENTS 5,251,299 10/1993 Masudaetal 395/182.08
A duplicate control and processing unit for telecommunications equipment consisting of two identical control units connected together is described. Each control unit (UC0. UC1) comprises a processing unit (UP0. UP1) which can be active or on standby, a peripheral data random access memory (RAM) for data processed during operation, and several peripheral circuits connected to the rest of the equipment. An EPROM (erasable programmable read-only memory) (CCL0. CCL1) in each processing unit contains the copy selection firmware. The data RAM and the peripheral circuits include a respective double gate access circuit (ACC0, ACC1) which allows selective access to the active processor only. The latter performs the writing cycles synchronously on both the duplicate data RAMs. allowing fast recovery of the operative synchronism by the standby processing unit, after switching due to failure of the active processing unit (FIG. 2).
6 Claims, 4 Drawing Sheets
