Paging Controlled Relay

The RDL TX-PCR1 is a paging-controlled relay designed to control audio switching from a constant-voltage amplified audio source. Its transformer-coupled input connects to a constant-voltage speaker line and responds to program material such as paging announcements. Switch-selectable support for 25 V, 70 V, and 100 V systems allows the same model to serve several common speaker-line configurations.

Ideal Use Cases

The TX-PCR1 is intended for distributed audio and paging systems that need switching to occur when audio is detected on an amplified speaker line. It is suited to applications where paging announcements or other program material must initiate a relay action without relying on a separate line-level audio feed. Detection covers 120 Hz to 7.5 kHz at the -3 dB points, providing a defined response range for monitoring program audio. The adjustable release delay also makes the relay useful when switching must remain active briefly after the detected material ends.

Why Choose This Model

This model combines audio detection, adjustable triggering, timed release, and relay switching in one device. Its input level is selected for 25 V, 70 V, or 100 V operation, while the trigger threshold is adjustable from 40 dB to -15 dB below the selected speaker-line voltage. A single-turn adjustment provides direct control over the threshold. The release delay is independently adjustable from 3 to 25 seconds, also through a single-turn control. These settings allow the response and release timing to be configured for the program material and system behavior.

Installation and Integration

The audio input accepts a transformer-coupled constant-voltage speaker line. During setup, the input selector is set to match the system’s 25 V, 70 V, or 100 V speaker-line level. The unit requires a ground-referenced 24 Vdc supply at 60 mA. Recommended power supplies are the PS-24AS for the USA and PS-24AX for international use; the power supply is not included.

For external control integration, the TX-PCR1 provides an open-collector control output rated at 25 mA on the SLAVE terminal. The switching contacts are rated for a maximum of 8 A at 250 Vac or 30 Vdc. When switching an amplified audio signal, the specified switching power is 500 W. Connected loads should remain within the applicable contact and switching-power ratings.

Performance Highlights

Three indicators make operating status visible: a blue LED for power, a red LED for threshold, and a green LED for the triggered state. Together, these indicators provide immediate confirmation that the unit is powered, show threshold activity, and identify when relay switching has been activated.

The adjustable trigger threshold helps determine the audio level at which the relay responds. Once triggered, the adjustable 3-to-25-second release delay controls the timing before release. This combination supports more deliberate switching behavior than a fixed-threshold, fixed-delay device. The specified 120 Hz to 7.5 kHz detection bandwidth focuses operation on a defined portion of the audio program signal.

What Makes It Different

The TX-PCR1 monitors an amplified constant-voltage speaker line rather than requiring an unspecified alternative audio source. Its selectable 25 V, 70 V, and 100 V input settings give installers one model for multiple constant-voltage system types. Threshold and release controls are both adjustable, while the SLAVE terminal adds a 25 mA open-collector control output alongside the relay contacts. The separate power, threshold, and triggered indicators also make the operating sequence easy to observe during setup and use.

The enclosure measures 3.17 inches wide by 1.76 inches high by 2.06 inches deep, equivalent to 8.05 by 4.47 by 5.23 cm. The listed WEEE weight is 0.41 lb. Shipping weight is 0.465 lb, and package dimensions are 2 by 2 by 4 inches.

Final Assessment

The RDL TX-PCR1 provides a focused solution for activating relay switching from paging announcements or other program material on a constant-voltage speaker line. Its selectable 25 V, 70 V, and 100 V input, adjustable threshold, adjustable release delay, status indicators, open-collector output, and rated switching contacts give integrators clearly defined controls and interfaces for paging-controlled audio switching.