The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 19, 1993
Filed:
Aug. 31, 1990
Hitachi, Ltd., Tokyo, JP;
Abstract
A private branch exchange having a comparatively small number of ISDN circuits, in the circuit interface a table is provided for the purpose of conversion between a logical channel lying between ISDN terminal equipment and the private branch exchange and one lying between the private branch exchange and an ISDN network. Such a private branch exchange refers to this table to recognize the correspondence of a user packet between ISDN terminal equipment and the private branch exchange to one between the private branch exchange and an ISDN network in order to perform packet switching on the D-channel. The use of this construction eliminates the need of any packet switching hardware, packet switching transmission line and high speed transmission line for communication between divided processors. Therefore, packet switching on the D-channel is possible without hampering the circuit switching performance of current circuit switching equipment.