Transmitter & Receiver Sets Of Token Less Single Line Block Instrument As Per Rdso Spe Cification No. Irs-S-98/2001 Amd-3(As Applicable,With Amd. Up To Date)Of Carrier Frequency 2700 Hz A Nd Modulated Frequency 65 Cycles/Sec.+/-1.5 Cycles-85Cyles/Sec+/-1.5 Cycles. [ Warranty Period: 3 0 Months After The Date Of Delivery ] ]