Telephone set TA-57. Demonstration of work in the field. 

Field telephone TA-57.
Phone Demonstration in the field through the wire P-274m
Telephone TA-57 - a brief description:
Adopted in 1957.
The communication range with the same type of device:
- when using wire P-274m - 35-40 km,
- when using wire P-268 - 40-45 km,
- using PVLS (PALC - Permanent Air Line Connections, 3..4mm steel wire) - up to 170 km.
Power - Battery GB-10U-1.3 (voltage 10 V) or battery "Krona" (voltage 9 V).
Operating time from one battery - up to 6 months.
Time to deploy and connect to the line - no more than 2 minutes.
Dimensions 222 × 165 × 80 mm.
Weight about 3 kg.