supply of electronic l.c. gate telephone systemelectronic l.c. gate telephone system,24v/12v dc power supply unit with maintenance free battery for electronic lc gate telephonesyste m as per rdso specification no: rdso/spn/tc-51/2011, rev 3.0 amdt-1 or latest. [ warranty period: 30 mo nths after the date of delivery ] , electronic l.c gate (slave) telephone. as per specification no. rdso/spn/tc/51/2011 revision 1 .0 or latest. [ warranty period: 30 months after the date of delivery ] , electronic l.c gate master telephone as per specification no. rdso/spn/tc-51/2011 revision 1. 0 or latest. [ warranty period: 30 months after the date of delivery ] , electronic l.c gate master telephone as per specification no. rdso/spn/tc-51/2011 revision 1. 0 or latest. [ warranty period: 30 months after the date of delivery ]