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:
Dec. 03, 2002
Filed:
Jul. 26, 2000
Applicant:
Inventor:
Rudolf Dollinger, München, DE;
Assignee:
Siemens Aktiengesellschaft, Munich, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M 1/24 ;
U.S. Cl.
CPC ...
H04M 1/24 ;
Abstract
Test functions to test an operability of a subscriber circuit are integrated in the subscriber circuit. The test functions use existing components and do not significantly burden the signal processor of the subscriber circuit. The subscriber circuit is provided in a digital telephone exchange having connectable subscriber lines and has a high-voltage section and a low-voltage section. Once an alternating current, which is produced by a tone generator, has been fed into connecting paths, a frequency-selective current threshold-value comparison is carried out, by which the operability of the subscriber circuit can quickly be confirmed.