The TA-57 can be used for induction calls working with 2-wire lines in an OB (local battery) or a ZB (central battery) operation. It can be used to transmit voice messaging in ranges between 0.3 and 3.4 kHz, with a calling frequency of 15 to 45 Hz. Absolute signal level at output of transmission path with a 600Ω load ranges between −3 and +3 dBu. It also a has a deployment time of 2 minutes. Power is primarily drawn from a 10V
lead–acid battery GB-U-1.3 (
ГБ-10-У-1.3) with a capacity of 1.3 Ah, alternatively a
9V block battery can be utilized. In OB battery operation, a
hand cranked magneto can be used to generate
ringing. A modernized variant of it is known as a TA-57U. == Users ==