RF Signal Protocol and Frequency Architecture
The SEWACall K-H2 wireless call button operates on a standardized 433.92 MHz radio frequency using Amplitude Modulation (AM). For commercial and industrial facilities deploying wireless paging networks, matching the carrier frequency and modulation type across peripheral hardware is critical to system reliability. The K-H2 transmitter operates with an internal working voltage of DC 12V and draws a minimal operating current of 10 mA during transmission pulses.
Power is delivered via an autonomous 23A 12V battery (they are not included). Because the unit relies entirely on independent internal power rather than wired low-voltage drops or power supplies, it operates completely untethered from facility electrical cabling, preventing ground loop issues and isolating the calling point from building electrical line variations.
Integration with SEWACall Centralized LED Display Receivers
The SEWACall K-H2 is designed for seamless integration with SEWACall centralized LED display receiver panels configured for 433.92 MHz reception. In centralized dispatch models—such as corporate pantry stations, administrative supervisor desks, restaurant kitchen order collection zones, and clinic nursing posts—the central receiver panel captures signals across an open-air transmission range of up to 100 meters. When a user presses a button, the panel receives the AM-modulated RF packet and displays the assigned room, cabin, bed, or table identifier instantly.
Attendant Wrist Pager and Mobile Receiver Interoperability
For mobile personnel who cannot monitor a wall-mounted panel continuously, the K-H2 integrates directly into SEWACall wearable attendant wrist pagers and attendant watch receivers operating on the 433.92 MHz band. The 2-key interface delivers two distinct functional commands across the wireless link:
- Call Transmission: Dispatches an immediate service request alert to the paired attendant wrist pager and central display station simultaneously.
- Cancel Transmission: Transmits an immediate cancellation command to clear the active notification on the attendant watch or LED panel, logging task fulfillment without requiring staff to walk to a central board.
Environmental and Enclosure Compatibility
With external dimensions of 60 mm x 60 mm x 22 mm, the K-H2 features a compact surface footprint suitable for flush mounting on walls, desks, conference room tables, and guest counters. The transmitter features a 100% waterproof enclosure, ensuring continuous hardware compatibility in high-humidity or splash-prone operational environments such as commercial bars, cafe outdoor dining spaces, healthcare sanitation areas, and office refreshment pantries.
Technical Compatibility Matrix
| Parameter |
Specification / Compatibility Value |
| Transmission Frequency |
433.92 MHz |
| Modulation Protocol |
AM (Amplitude Modulation) |
| Receiver Compatibility |
SEWACall 433.92 MHz LED display receivers and attendant wrist watch pagers |
| Input Power Supply |
23A 12V battery (they are not included) |
| Operating Current / Voltage |
10 mA / DC 12V |
| Effective Range |
Up to 100 meters (open area) |
| Enclosure Protection |
100% Waterproof |
| Form Factor Dimensions |
60 mm x 60 mm x 22 mm |
| Harmonized System Code |
HSN 85176910 |
Multi-Unit Grid Scalability
Because the unit uses an open wireless link over 433.92 MHz, facility engineers can deploy dozens of K-H2 transmitters across corporate cabins, meeting rooms, or hospitality tables to interface with a single centralized receiver infrastructure. The lack of signal wiring allows quick relocation, reassignment of transmitters, and rapid network expansion without structural modifications or downtime.
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