Multiple link circuit for a port multiplexer

Abstract

A multiple link circuit for coupling a plurality of telephone lines to the ports of a port multiplexer without requiring the splitting of C-leads is disclosed. The multiple link circuit includes an internal priority determining arrangement that eliminates the need for individual links to be scanned by an address scanner. Each link of the multiple link circuit is bridge connected to a C-lead and includes: a busy detector for detecting the busy status of the C-lead; and, a control circuit for controlling the coupling of a subscriber seized telephone line to the associated port. The priority determining arrangement prevents any lower priority control circuit from coupling a seized telephone line to the associated port if any higher priority line is simultaneously attempting to be so coupled. After signal processing (performed by a signal processor connected to the port) has ended, or some other release action occurs, a port generated release signal disconnects the seizing link from the port. While any link is connected to an associated port, make-busy ground circuits forming part of each link apply false busy status information to all of the C-leads connected to the other links of the multiple link circuit. The false busy status information prevents the linefinders associated with these other links from attempting to seize the busy port via those links. Termination of the conversation flowing through one link creates a WINK signal that causes the linefinder to release the associated line, if another link is connected to the associated port at the time the conversation is terminated.