The S4T-771-S is the dual-angle sensing block with a tone sounder added. Four analogue channels are in use — 1 and 4 for the two optical scatter angles, 2 for heat and 5 for alarm-device faults — and EN 54-3, 5, 7, 17 and 18 appear on the plate.
Against the S4T-770-S the addition is channel 4, the backward-scatter reading; against the silent S4T-711 the addition is the sounder and its fault channel. It is the busiest of the tone-sounder parts on the loop's analogue map, at four values per address.
Gent publishes manufacture-time baselines for all four channels on this part, which is the reference point drift is measured against in service. Where speech rather than tone is wanted on the same block, the part is the S4T-711-V.
Technical data
| Sensing elements | Forward- and backward-scatter optical smoke sensors and heat sensor |
| Label marking | O²H/S |
| Analogue channels | 1 optical (forward), 2 heat, 4 optical (backward), 5 alarm faults |
| EN 54 parts declared | EN 54-3, 5, 7, 17, 18 |
| Sounder current | 2 mA average; 4.5 mA maximum in Turbo mode |
| Baseline at manufacture (Tnew) | Channel 1 optical 25; channel 2 heat 66; channel 4 optical 40 |
| Baffle ring | White |
Specifications from Gent 4188-1130 issue 1 (12/23).
Compatibility
Fits the S4-700 base with the S4-705 IP21C plate. Self-Test needs the Vigilon loop of a Vigilon plus or Compact plus panel on compatible firmware.
Installation
Expect four analogue values against this address once commissioned; three optical and heat readings with no channel 5 means the panel has it typed as a plain dual-optical head. Sound levels are set per device, with 65 dBA at 1 m the floor for compliance.
Full details: S-Quad Self-Test (S4T) Data and Installation — 4188-1130 · 28 pages · technical data, sounder information and the manufacture-time analogue baselines for each channel
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