RDL STVOX-1 Specifications

STICK-ON® SERIES

Model ST-VOX1
Voice Activated Relay

ANYWHERE YOU NEED...

• Control Switching from Voice Signal

• Audio Switching Precisely Tailored for

Stable, yet Fast Switching from Voice
Sources

• Switching from Mic or Line Level Signals

• Precise Threshold Adjustment

• DPDT Switching Contacts

• Open-Collector Slave Output

You Need The ST-VOX1!

APPLICATION: The ST-VOX1 is an audio controlled relay in the group of STICK-ON series products by
Radio Design Labs. These products are designed for quick, convenient installation and reliable operation
in a variety of control applications. The ST-VOX1 is specifically designed to switch reliably on voice
signals.

When used in intercom or talk-back applications, the ST-VOX1 may be triggered directly from an
unbalanced microphone. In many such installations, the microphone or other audio source must be
preamplified, making the ST-VOX1 an ideal mate to work with RDL’s STM-1 preamp. The unbalanced
output from the STM-1 can be used to trigger the ST-VOX1, while the STM-1 balanced output is used for
the audio feed.

The ST-VOX1 releases very quickly, but holds on through very short pauses in syllables common to
speech. These time constants allow the design of a communications system yielding comfortable two­way conversation.

• High-impedance inputs connect across any unbalanced audio line

• Multi-turn sensitivity adjustment permits precise threshold setting

• Multi-turn DELAY control adjusts relay release delay

• Tight bandpass filtering yields triggering on voice frequencies

• Slave open-collector terminal allows additional relays to be added for more contacts (RDL’s ST-LCR1)

• Slave terminal may be used with remote switch to manually override the control circuit and turn on the

relay

Wherever a voice activated relay is needed, the ST-VOX1 is the ideal choice. Use the ST-VOX1
combined with other RDL RACK-UP®, STICK-ON, TX™, or FLAT-PAK™ series products as part of a
complete audio/video system.

RDL •• P.O. Box 1286 •• Carpinteria, CA., USA 93014 •• [phone] •• FAX [phone] •• http://www.rdlnet.com

STICK-ON® SERIES

Model ST-VOX1
Voice Activated Relay

Installation/Operation

EN55103-1 E1-E5; EN55103-2 E1-E4

Typical Performance reflects product at publication time
exclusive of EMC data, if any, supplied with product.
Specifications are subject to change without notice.

TYPICAL PERFORMANCE
Mic Input: 5 kΩ unbalanced line
Line Input: 200 kΩ unbalanced
Control Outputs: Open-collector @ 100 mA, Suitable to drive indicators or “slave” LCR
Relay Contacts: Double-Pole-Double-Throw
Maximum switching power: 60 W, 125 VA
Maximum switching voltage:220 Vdc, 250 Vac
Maximum switching current: 2 amps
Maximum carrying current: 3 amps
Mic Input Sensitivity: Adjustable -80 dBv to -50 dBv
Line Input Sensitivity: Adjustable -45 dBv to -15 dBv
Release Delay Time Adjustment Range:

Activation Response Time:

Power Requirement: 24 to 33 Vdc @ 50 mA, Ground-referenced
* Time required for normally open contacts to switch

891-0034I

Relay Contacts*: 70 to 260 ms
Slave (open collector output): 15 to 260 ms

Relay Contacts*: 5 ms

Slave (open collector output) 3 ms

Radio Design Labs Technical Support Centers

U.S.A. [phone], [phone]; Fax: [phone]

Europe [NH Amsterdam] (++31) 20-6238 983; Fax: (++31) 20-6225-287