supply of 02 channel voice data recording and processing unit (vdrpu)02 channel voice data recording and processing unit (vdrpu),supply of 02 channel voice data recording and processing unit (vdrpu) as per. rdso / spn / tc / 38 - 2002 ver 2 or latest. [ warranty period: 30 months after the date of delivery ] ] , supply and installation of 02 channel voice data recording and processing unit (vdrpu) as per. rdso / spn / tc / 38 - 2002 ver 2 or latest. [ warranty period: 30 months after the date of delivery ] ] , supply and installation of vhf receiver to record communication with in the radio coverage area of station vhf equipment. note: vhf based secured communication equipment has in-built vhf radio which is configured on dg (driver guard) frequency to record communication. if railways also wants to rec ord communication on shy frequency simultaneously, then this is required per location. [ warranty perio d: 30 months after the date of delivery ] ]