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September 08, 2026 6 min read
Installation and operation manual for the STI Repeater, Model STI-34109 — a 433 MHz wireless range extender for STI sensors.
Installation and operation manual for the STI Repeater, Model STI-34109 — a 433 MHz wireless repeater that doubles the transmission range between STI wireless sensors and STI receivers.
The STI REPEATER is a 433 MHz radio signal receiver and transmitter that effectively doubles the transmission range of STI sensors to STI receivers. It filters out any radio signal not using the 433 MHz STI protocol. When any STI protocol signal packet is received (except from an STI 8-Channel Receiver), it retransmits the same signal packet. There is no limit to the number of STI sensors that can be used with a REPEATER.
Important: multiple REPEATERS should NOT be used within reception range of each other — a REPEATER will retransmit any STI protocol signal packet, so two REPEATERS in range of each other can bounce signal packets back and forth repeatedly. If a dual-REPEATER system or further extended range is needed, use an STI 8-Channel Receiver (STI-34108) instead — it retransmits alert/trouble notifications (not the raw signals themselves), so REPEATER feedback does not occur. The 8-Channel Receiver works with up to 8 different STI wireless sensors.
| External Supply | 9–18V AC or DC, 15 mA nominal (recommended 30+ mA rating) |
| Backup Batteries | Three (3) 1.5V AAA Alkaline — external power backup (up to 72 hours) |
| Housing Dimensions | 4 x 6 3/8 x 1 1/4 in. |
| Antenna Length (inserted) | 7 3/4 in. |
The REPEATER receives distant STI protocol sensor signals and repeats the information to the receiver. STI sensors typically send 8 identical signal "packets." The REPEATER rejects any signal that is not an STI protocol packet and retransmits the complete 8-packet set to the receiver.
The receiver can monitor the REPEATER's supervision and trouble signals when it is enrolled (optional). To manually send a REPEATER signal, press and release the tamper switch — the red LED should blink. To enroll sensors, follow the receiver's programming instructions.
| LED | Solid ON | Blinking |
|---|---|---|
| Green LED | AC/DC power on | Signal Received |
| Red LED | Low Battery Alert (only with AC/DC power on) | Signal Transmitted |
The REPEATER is intended to be mounted indoors or in a waterproof environment. Review the Applications Guide (below) for suggested setups.
The manual illustrates several supported system layouts (diagrams included in the original PDF):
Note: the original PDF includes detailed wiring diagrams and DIP switch (SW4/SW5) configuration tables for mirror master/slave settings and siren time options for each layout — see the downloadable PDF for the full visual reference.
This product has been tested and complies with the specifications for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used per instructions, may cause harmful interference to radio communications; there is no guarantee interference won't occur in a particular installation.
If this equipment causes harmful interference to radio or TV reception (determined by turning the equipment off and on), try: reorienting or relocating the receiving antenna; increasing separation between the equipment and receiver; connecting the equipment to a different outlet; or consulting a dealer or experienced radio/TV technician.
Operation is subject to: (1) this device may not cause interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. Changes or modifications not expressly approved by Safety Technology International, Inc. could void your authority to operate this equipment. This product meets applicable Industry Canada technical specifications.
FCC ID: U5X-RE324 | IC: 8310A-RE324
FOR INDOOR USE ONLY. Keep away from water or damp areas.
Safety Technology International, Inc. warrants to the original consumer/purchaser that this product is free of defects in material and workmanship under normal use for a period of one (1) year from the original date of purchase. Electronic warranty registration available at www.sti-usa.com/wc14.
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