Yerevan Computer Research

Development Institute


The device is designed for operational selective loudspeaker communication with dispersed remote objects via various communication channels.

Technical characteristics 

  • simplex connection between two subscribers, as well as between the subscriber and the central panel on the mutual distance of 40 km;
  • simplex connection between to subscribers via a separate channel.
  • circular communication (conference) in the network for up to 10 subscribers, for two of which communication is carried out via a radio channel;
  • emergency call to all subscribers and message transmission from the central console;
  • transfer from an external microphone with PTT(push to talk);
  • reception on the built-in speaker or headphones;
  • light and sound alarm call; 
  • capacity to call to the central console from the subscriber disconnected from the network;
  • differential system automatic setting mode
  • capacity to connect the TA-57 field telephone set to the subscriber's equipment;
  • compatibility with other standard loudspeaker equipment in simplex mode;
  • good sound quality with verbal intelligibility of at least 95%;
  • operating temperature range from 50 to 500C;
  • power from the commercial power supply 220 VAC or DC voltage = 12V.

Network channels

  • physical two-wire line, a radio relay line, PM channel - up to 8 channels;
  • radio communication through external radio stations with PM input - up to 2 channels.


  • the CPU has a toggle switch to enable / disable any subscriber to the circular communication network;
  • a subscriber disconnected from the network can notify the CPU whether he wants to join the network by pressing the "call" button, after which the CPU operator can connect this subscriber to the network;
  • the subscriber connected to the network via radio can listen to everything, and he can only listen to the other while holding down the PTT CPU;
  • for connecting subscriber TA-57 to the network operator of the AP to which it is connected, it must be in the network and corresponding toggle switch access TA-57;
  • capacity to connect two APs via a separate communication channel;
  • capacity of local communication between the AP and TA-57 via a two-wire physical line up to 40 km long;
  • to call a subscriber from the AP side, it is enough to press the "call" button, and from the TA-57 side, the call is made by rotating the inductor of the device.