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. 17, 1989
Filed:
Aug. 20, 1986
Rong-Chin Fang, North Andover, MA (US);
American Telephone and Telegraph Company, AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
A channel unit is disclosed for interfacing a digital subscriber line (DS1) to a PCM digital transmission facility, for example, T carrier. The basic rate interface (BRI) 2B+D format is converted to a unique three time slot format for transmission in the DSl PCM signal format. The two communication B channels are interrogated to determine if they have a logical 0 in each bit position, i.e., zero byte. If so, a non all logical 0 bit pattern is substituted and a logical 1 indication bit is inserted in an associated bit position in a control channel. In a receiver, the associated indicator bit positions in the control channel are interrogated to determine if an all logical 0 bit pattern, i.e., a zero byte, had been replaced. If so, an all logical 0 bit pattern is inserted in the associated communication channel. A logical 1 is inserted in bit position 2 of the control channel to negate the possibility of emulating a T carrier yellow alarm condition. A logical 1 is also inserted in bit position 3 of the control channel to satisfy the logical 1's density requirement for digital transmission facilities.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile