To be clear then, my subscriber loop may have a DC resistance of 150ohms due to the physical loop length but should have an AC impedance of 600ohm (+/- a few)? I have to assume that as the telco cable guy was performing the test he's telling me the AC impedance.
If so, then would I need to insert some sort of complex impedance network to build out a match rather than just a single resistor? > -----Original Message----- > From: Rich Adamson [mailto:[EMAIL PROTECTED] > Sent: October 12, 2004 2:58 PM > To: Asterisk Users Mailing List - Non-Commercial Discussion > Subject: Re: [Asterisk-Users] Chaining more than one zap echo > canceller? > > > Adding resistance to one side of the line only begs for problems > as it creates a tip-ring imbalance that will "cause" echo, etc, > when other imperfections exist. > > If that approach works at all for anyone, its addressing a symptom > and not the root cause. > > Try this one: Each customer loop is made up of copper and the longer > the copper, the more resistance. Yet the impedance (in the US) is > consistently 600 ohms. A short loop might be a 100 ohms while a long > loop might be well over 1500 ohms; still both are 600 ohm impedance. > > ------------------------ > > > Impedance is the measure of total opposition (resistance, > capacitance, > > and inductance) to alternating current flow. Adding > resistance will > > raise the impedance of the line. > > {clip} _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
