US Patent 7539301 Cost-effective multichannel digital logger

A digital logger system includes a multichannel interface circuit that:1. concurrently and continuously receives audio telecommunication signals for at least two telephone calls; and2. continuously transmits linearly encoded digital audio data representing the received audio signals.A Universal Serial Bus (“USB”) hub of the system receives the transmitted digital data for retransmission to a USB root hub. A USB root hub of personal computer (“PC”) receives transmitted digital data, and executes PC software which continuously monitors the digital data for embedded line status and signaling information including a telephone line “going off hook.” When a telephone line goes “off hook,” the software records both:1. an audio header that stores information about a telephone call; and2. an audio file that stores compressed digital data for the telephone call.