... multiplexing;Supports network of point to point, chain and ring, providing functions like tributaries 1+1 channel protection, ... REF) Standard ITU-T G.813/783Input T1, T3Output T4Working mode: tracing, holding & free runInterface Micro-mini coaxialEngineer Order ... interface Bit Rate 64Kb/sSignal mode Dual tone multi-frequency dialing modeRing frequency 450HzRing mode BuzzerNE address range 00~99Serial ...