Patent ID: 6906526
Filing Date: 2005-06-14
Classification: G01R,H04L,H04N

Abstract:
1. A method for individually monitoring the connectivity status of a plurality cables, each cable connected at a respective port on a cable modem termination system (CMTS) having switching interfaces between primary and secondary routers, the cables conducting upstream and downstream RF communication signals on parallel paths having a nominal system impedance, whereby the monitoring is self-contained within the CMTS, comprising the steps: a) producing a sinusoidal reference signal having a frequency outside the frequency range of the RF communication signals; b) injecting the reference signal onto the parallel RF communication signal paths; c) individually detecting on each path, the power level of the reference signal, whereby the power level correlates with an expected cable load impedance and the detecting occurs within the CMTS boundary; d) producing a DC control voltage for each path based on the detected power level of the reference signal on each path; e) determining the connectivity statuses of the connected cables based on the DC voltages of step d); and f) generating a cable status indicator for each RF port cable.