procurement of one set of three items etc, one set consisting of three items as per annexure a 1 ) master telephone unit with voice logging facility for electronic lc gate telephone system as per specification no. rdso / spn / tc / 51 / 2011 rev 1.0 or latest with all accessories 2 ) supply of gate telephone ( slave telephones ) for electronic lc gate telephone system as per specifition no rdso / spn / tc / 51 / 2011 rev 1.0 or latest with all accessories 3 ) supply of power supply system with mf battery of 12v / 24v dc ( 12v dc supply shall be connected to the station telephone unit & 24v shall be fed to line circuit ) with maintenance free battery for electronic lc gate telephone system as per specification no. rdso / spn / tc-51 / 2011, rev 3.0 amd.1 or latest including battery charger &all accessories. [ warranty period: 30 months after the date of delivery ]