Paging Sound Detector - Radio Design Labs TX-PSD1

The TX-PSD1 is the ideal choice in many applications where switching needs to be controlled from a constant-voltage amplified audio source. The module will trigger on any program material, with paging sources being the most common. The TX-PSD1 provides an open-collector SLAVE output to control other modules or equipment when a paging signal is detected.

The amplified audio source is connected using a detachable terminal block. A front-panel switch is provided to select the source type: 25 V, 70 V or 100 V. The 25 V setting may be used for an 8 ohm, 75 Watt maximum, amplified source. Input sensitivity is adjusted on a single-turn trimmer. In the clockwise position, the SENSITIVITY trigger threshold is 30 dB below the switch-selected constant voltage. A red LED illuminates whenever the audio level exceeds the trigger threshold, facilitating the sensitivity adjustment.

The module is triggered when the audio exceeds the threshold and it remains triggered for a defined time duration after the audio falls below the threshold. This DELAY is adjustable from 3 to 25 seconds using a front-panel trimmer. Adjustment is simplified by a green LED that remains illuminated while the module is triggered. The SLAVE terminal may be used as either an input or output control terminal. When the module is triggered, the SLAVE terminal is internally pulled to ground through an open collector. If the TX-PSD1 SLAVE terminal is externally pulled to ground through a switch or the open-collector terminal of another RDL module, the relay will energize until the terminal is released.

A blue POWER LED illuminates when the TX-PSD1 is powered from an external 24 Vdc power supply.

Use the TX-PSD1 to control RDL modules or other equipment with ground activated control inputs that permit a 24 V pull up.