ST-ACR1

RDL ST-ACR1 - Line-Level Audio Controlled Relay (0.5 to 5 s)

The RDL ST-ACR1 is a line-level audio controlled relay module designed for automatic switching in response to audio signal presence. Part of the STICK-ON® series, it offers compact form factor, easy installation, and reliable performance in professional AV applications.

The ST-ACR1 detects audio signals from -30 dBu to 0 dBu and activates a DPDT (double-pole, double-throw) relay. The release delay after the signal drops below the threshold is adjustable from 0.5 to 5 seconds. A threshold LED assists in precise sensitivity calibration.

Its high-impedance bridging input allows connection across any balanced or unbalanced audio line without affecting the signal. The open-collector SLAVE output enables control of additional relays or indicators.

Functionality

• Automatic switching triggered by audio signal presence
• Sensing of balanced or unbalanced line-level signals
• Adjustable sensitivity threshold and release delay
• LED indicator for accurate threshold setting
• SLAVE open-collector output for controlling additional modules
• Manual override via external switch

Features

• Relay type: DPDT (double-pole, double-throw)
• Input sensitivity: -30 dBu to 0 dBu (adjustable)
• Release delay: 0.5 to 5 seconds (adjustable)
• Activation response time: 25ms
• Retrigger delay: 250ms
• Max switching current: 2A
• Max switching voltage: 220V DC, 250V AC
• Max switching power: 60W, 125VA
• Audio input: 10kΩ balanced bridging
• Power requirement: 24V DC, 50mA (max SLAVE load 20 mA)
• Control output: open-collector, 25mA
• Operating temperature: 0°C to 55°C
• Mounting: STICK-ON module - compact and integration-friendly

The RDL ST-ACR1 is a dependable solution for AV installers needing automatic control based on audio signal detection. Ideal for paging systems, AV automation, educational and commercial installations.