The GST I-9403 Intelligent Sounder Strobe features a two-part mechanical design comprising an ABS plastic enclosure and a detachable mounting base. This modular structure enables pre-wiring of field circuits prior to head insertion, protecting internal electronic assemblies during rough-in electrical construction. The standard shallow base measures 110mm in diameter by 95.9mm in total assembled height, with a total weight of approximately 327.2g.
Mechanical Base Mounting and Conduit Considerations
The standard shallow base incorporates pre-formed mounting holes engineered to accommodate fixing pitches from 55mm to 80mm and up to 83mm, allowing direct installation onto standard electrical backboxes or flat architectural surfaces. For industrial installations requiring surface conduit entry, external raceways, or exposed fire-resistant cabling, the optional GST C-94DB deep base (Product No. 30203792) must be utilized. Environmental installation parameters require verification of operating conditions between -10°C and +50°C with relative humidity levels not exceeding 95% non-condensing, consistent with its IP33 ingress protection rating.
Field Wiring and Terminal Connections
Field wiring must be completed using fire-resistant cable with a minimum cross-sectional area of 1.5mm² (or above, as governed by local fire engineering regulations). All termination terminals are located on the base assembly to maintain circuit continuity during device servicing:
- Loop Terminals Z1 (Terminal 2) and Z2 (Terminal 4): Non-polarized addressable communication loop connections to the compatible fire alarm control panel (GST100, GST200-2, GST200N, or GST-IFP8). Operating loop voltage range is 20VDC to 28VDC (24VDC nominal).
- External Power Terminals D1 (Terminal 9) and D2 (Terminal 7): Non-polarized 24VDC auxiliary power supply connections (acceptable range 20VDC to 28VDC). Required when operating the sounder strobe in normal consumption mode or when loop capacity thresholds are reached.
Power Mode Engineering and Loop Capacity Constraints
System designers and commissioning technicians must balance device power modes against panel circuit loading:
- Loop-Powered Mode: When powered directly from the fire detection loop without external 24VDC cabling, only the power-saving mode is permitted. A strict maximum limit of 20 sounder strobe units can be driven per detection loop. Loop monitor standby current is ≤2mA and start current is ≤9mA per device. Attempting to run normal consumption mode directly on loop power is prohibited.
- External 24VDC Powered Mode: When powered via dedicated 24VDC lines across terminals D1 and D2, the loop communication current drops to ≤1mA standby and ≤2mA start. In normal consumption mode under external 24VDC, the power supply circuit draws ≤1mA standby current and ≤35mA start current, delivering peak acoustic output (86dB for Tone 14 and 84dB for Tone 16 at 1m). In power-saving mode with external 24VDC, the power start current drops to ≤9mA.
Electronic Addressing and Programmer Configuration
The GST I-9403 is electronically addressed using the GST P-9910B handheld programmer (Product No. 10104894) across an address spectrum of 1 to 242. Device configuration must be performed before locking the head into the base:
- Factory Default: Configured out-of-the-box for Tone 14, single address operation, and normal consumption mode.
- Single vs. Dual Address Setup: The device can be assigned a single address or dual addresses. In dual-address Evacuate + Alert staging, activating the primary address sounds the pre-alarm tone (800Hz pulsed 1s off / 1s on at 76dB), while the secondary address engages the main evacuation tone.
- Tone and Output Selection: Programmers can select from 16 alarm tones (Tone 14 at 2400Hz–2900Hz @ 3Hz and Tone 16 at 500Hz–1200Hz, 3.75s / 0.25s off are LPCB-recognized). Specific applications can also isolate operation by electronically switching off either the sound output (strobe-only notification via the high-intensity LED cluster) or the light output (sounder-only notification).
