supply of supply, transportation ,installation, and commissioning of 04-channel voice logger , supply, transportation ,installation, and commissioning of 04-channel voice logger as per rd so/spn/tc/38-2002 ver2 or latest to record for vhf/other 2 wire communication , consisting of : 4 channel vdrpu, 13.5v/15 amp smps, 12v/65ah smf battery, 6u wall mount rack. all materials required for installa tion and commissioning to be arranged by contractor. (includes power cable and other inter connecting ca bles). note: user manual to be along with equipment. necessary training related to maintenance and opera tion to be imparted to all concerned railway staff. all materials required for installation and commissioning to be arranged by contractor (includes power cable and other inter connecting cables).as per attached spe cification and annexure [ warranty period: 30 months after the date of delivery ] ]