The current published FCC Part 68 regulations still call for 150 VRMS ringing with 56.5 VDC superimposed for a Type "B" REN, which is 269 volts -- any MOV less than 270 is rather risky. Also, I believe that the new EIA/TIA 470B calls for a higher DC bias during 150 VRMS ringing -- we have seen several telephone products burn up during that testing.
________________________________________________________________ John Combs, Senior Project Engineer, ITS/TestMark Laboratories Email: [email protected] URL: http://www.testmark.com
