Radio Frequency and Wireless Transmission Protocol
The Sewa Model KW1P Wireless Nurse Call Washroom Pull Cord Unit operates via radio frequency on an Amplitude Modulation (AM) transmission standard at 433.92 MHz. This dedicated wireless band allows the transmitter to send rapid emergency call and cancellation packets to matching wireless monitoring hardware without hardwired network cabling. Operating across an open-air transmission line-of-sight range of up to 100 meters, the transmitter interfaces directly with 433.92 MHz wireless nurse call system receivers and signal repeaters. For facilities spanning multi-story wings or expansive floor plans, the unit supports deployment alongside optional wireless signal boosters to extend carrier coverage from remote washrooms back to base receivers.
Central Nurse Call Display Receiver Integration
Engineered for facility-wide monitoring networks, the KW1P pull cord unit is cross-compatible with multi-channel central nurse call display panels and desk/wall-mounted visual receiver consoles located in duty stations, security rooms, or nursing hubs. When the mechanical pull cord is pulled, the unit broadcasts an alert signal registered by the central display panel, which identifies the triggering washroom number or location identifier. Once facility personnel attend to the user, pressing the dedicated cancel button located directly on the 85 mm x 85 mm x 10 mm faceplate immediately transmits a cancellation signal on the 433.92 MHz AM frequency, clearing the alert from the central display receiver.
Corridor Overdoor Lights and Local Siren Alarms
To enable immediate visual and audible alerting in the direct vicinity of an incident, the transmitter integrates with external corridor door indicators and local siren alarm hardware installed directly outside the restroom door. Activating the pull cord simultaneously registers on these secondary corridor enunciators, alerting passing staff to the specific stall or washroom requiring emergency entry. The integrated dual-key design—comprising pull cord activation and front-facing push cancellation—ensures that audio-visual alarms at the corridor indicator can be silenced and reset directly at the washroom unit once assistance is rendered.
Electrical and Enclosure Specifications
The unit functions as an autonomous wireless node powered by a DC 12V operating circuit with an ultra-low working current of 10 mA. Internal power is supplied by a 23A-12V battery (they are not included), eliminating the need to tie into building mains power or conduit infrastructure during retrofit projects. Built with an ABS plastic chassis weighing 0.275 kg, the flush-profile enclosure mounts near toilet fixtures in clinical, commercial, or public facilities.
| Parameter | Specification / Compatibility Baseline |
|---|---|
| Wireless Modulation & Frequency | AM (Amplitude Modulation), 433.92 MHz |
| RF Transmission Range | Up to 100 meters in open field conditions |
| Range Extension Options | Compatible with 433.92 MHz optional wireless signal boosters |
| Receiver Hardware Compatibility | Central nurse call display panels, multi-washroom security displays |
| Local Alert Hardware Compatibility | External corridor door indicator lights, local audio siren alarms |
| Control Architecture | 2-Key functionality: Cord pull emergency call trigger, local push cancel |
| Electrical Operating Profile | DC 12V working voltage, 10 mA working current |
| Power Cell Requirement | 23A-12V battery (they are not included) |
| Chassis Form Factor & Material | 85 mm x 85 mm x 10 mm, ABS plastic housing, net weight 0.275 kg |
