The explosion-proof subscriber calling device PKV "Trombone SORS-AVU" (hereinafter referred to as AVU) is a component of the "Trombone SORS" Voice Feedback System (hereinafter SORS). The AVU is designed to receive and transmit voice messages between a subscriber located in an explosion-hazardous area and the dispatcher. The dispatcher uses another component of the "Trombone SORS" system - the "Trombone SORS-PD" dispatch console (hereinafter PD) - to receive and transmit voice messages. Messages are transmitted using the main component of the "Trombone SORS" system - the "Trombone SORS-LBS" local communication unit (hereinafter LBS). Each LBS can connect one dispatch console and up to four communication lines with the AVU, with up to 8 AVUs installed in each communication line. Up to 16 LBS devices can be used in the SORS.
The SORS system allows for two simultaneous communication sessions. All SORS system components are connected via a digital communication line (RS485 interface) up to 1,200 meters long.
The Trombone SORS-AVU intercom system is a terminal subscriber intercom device that can be installed in hazardous areas of industrial enterprises and facilities, and as part of the Trombone SORS system can be used to build:
Structurally, the AVU consists of two housings – the device housing and the housing of the junction box, connected by an adapter.
The AVU belongs to electrical equipment groups II and III according to GOST 31610.0-2019 (IEC 60079-0:2017) and is intended for use in hazardous areas and outdoor installations in accordance with the explosion protection marking "1Ex db IIC T6 Gb X / Ex tb IIIC T85°C Db X" for the device enclosure and "1Ex db IIC T6 Gb X / Ex tb IIIC T80°C Db X" for the junction box enclosure according to GOST IEC 60079-1-2013. AVU can be used in class 1 and 2 hazardous areas according to GOST 31610.10-1-2022 (IEC 60079-10-1:2020).
The AVU is designed for operation at ambient temperatures from 0°C to +40°C and atmospheric pressures from 84 to 106.7 kPa. The device has a UHL1 climate rating in accordance with GOST 15150-69 and a dust and moisture protection rating of IP66 for the device enclosure and IP66/IP67 for the junction box enclosure in accordance with GOST 14254-2015 (IEC 60529:2013).
| Power supply voltage, constant, via communication line from Trombone SORS-LBS | 8-36 V* |
| Power consumption no more than | 0.4 W |
| Port for communication with Trombone SORS-LBS and other AVUs | RS485 |
| Number of RS485 ports (connectors) for communication with LBS and other AVU | 1(2) |
| Maximum length of communication lines with LBS | 1200 m |
| Overall dimensions of the AVU without cable entries, no more than | 333x146x100 mm |
| Weight of the AVU, no more than | 3.5 kg |
| Body material | aluminum alloy |
| Operating temperature range | 0…+40°С |
| Degree of protection of the shell: - device body - junction box housing |
IP66 IP66/IP67 |
* When designing a SORS system, it is also necessary to take into account the range of supply voltages of emergency signaling devices that can be connected to the ACU and powered by the same voltage.
The ACU kit can include up to three explosion-proof KV series cable glands, KV TU 27.33.13-359-81888935-2019. The connecting thread of the cable glands is M20x1.5. The cable glands allow the input and output of round cables of various diameters:
EAEU RU C-RU.AZh58.B.03102/22. Certificate of Conformity to TR CU 012/2011 "On the Safety of Equipment for Work in Explosive Environments" OPERATING MANUAL. EXPLOSION-PROOF SUBSCRIBER CALLING DEVICE PKV "Trombone SORS-AVU" 3D MODEL OF THE EXPLOSION-PROOF SUBSCRIBER CALLING DEVICE PKV "Trombone SORS-AVU" 
