120-Zone IP Public Address System with Automatic Fire Alarm Integration and Code Blue Announcements

The hospital's existing public address system was a conventional analog installation dating from the building's 2008 construction. In its original specification, it had served adequately for a smaller occupancy, but as the hospital expanded its bed count and clinical programme through successive renovations, the PA coverage had become fragmented and unreliable.

The most critical operational gap was Code Blue announcement. Code Blue — the emergency call for a patient cardiac or respiratory arrest requiring immediate resuscitation team response — depends entirely on rapid and clear announcement throughout the facility. At this hospital, Code Blue announcements were made by the nursing station dialling a central operator and requesting the announcement over the PA. The central operator then manually made the announcement using a handheld microphone. The process had two documented failure modes: first, the nurse station phone might be engaged or unanswered at the operator; second, the PA announcement was sometimes not heard in the ICU because the ICU had a dedicated sound zone that had been disconnected from the main PA system during a renovation in 2018 and never reconnected. Two Code Blue incidents had resulted in delayed resuscitation team response — measured at 4 minutes and 6 minutes respectively from the call to room arrival — in areas where the announcement had not been heard. Resuscitation outcome data at the hospital showed that survival rates from in-hospital cardiac arrest are strongly time-sensitive; the medical director had calculated that both delayed responses occurred within the time window where intervention could have altered outcome.

The fire alarm integration gap was a separate but related problem. When the hospital's Siemens fire alarm panel detected a fire or was manually triggered, the building's evacuation response depended on staff manually making a PA announcement. There was no automated link between the fire alarm system and the PA. In a drill exercise conducted by the hospital's fire safety officer, the evacuation announcement was delayed by 2 minutes and 20 seconds from alarm activation to PA announcement — entirely because the staff member responsible for making the announcement was on the phone when the drill alarm activated and had to be physically alerted by a colleague before making the announcement.

The hospital also had significant coverage gaps from the original PA system: Floors 8 and 9 (which had been added during a building extension in 2015) had PA coverage from a standalone sub-system that was not connected to the main PA panel. The basement car park, ambulance bay, and loading area had no PA coverage. Several patient waiting areas had speakers that had ceased functioning but not been replaced, leaving waiting patients unable to hear appointment call announcements.

Background music in waiting areas — a known contributor to patient experience scores, which the hospital's management was tracking as part of a service improvement programme — was entirely absent. The damaged speakers in waiting areas were producing no audio at all.

SSAL designed and deployed a 120-zone IP public address system using DSPPA IP-8000 series hardware across all 11 levels of the hospital.

DSPPA IP PA System — Core Architecture: The DSPPA IP-8000 network audio server was installed in the hospital's IT server room, connected to the hospital's data network via dedicated VLAN (VLAN 50). The IP-PA system differs fundamentally from conventional analog PA: each zone is defined in software on the server, speaker zones can be combined, subdivided, or reconfigured without physical wiring changes, and emergency priority messages automatically override all other audio on all zones simultaneously.

The 120 zones were mapped to the hospital's physical layout: each ward floor is divided into 8-12 zones (corridor, nurse station, patient bay areas, utility rooms), the ICU and operating theatres each have dedicated zones with independent volume and priority management, waiting areas and public spaces are separate zones with background music capability, and emergency/service areas (basement, ambulance bay, loading dock) are individual zones.

PoE IP Ceiling Speakers — 380 Units: 380 DSPPA PoE IP ceiling speakers (DIP-A8206N, 6W, 8 Ohm) were installed throughout the building. Each speaker receives both power and audio data over a standard Cat6 network cable from PoE switches — eliminating the separate speaker cable and 100V line transformer runs that conventional analog PA systems require. This dramatically simplified the installation in the existing building, as the hospital's IT network infrastructure (Cat6 cabling and PoE switches) already reached every room, while new dedicated speaker cable runs would have required extensive and disruptive cable tray installation.

In the ICU and operating theatre areas, flush-mount ceiling speakers with airtight back-boxes were specified to maintain ceiling infection-control integrity. In external areas (ambulance bay, basement car park), IP66-rated weatherproof wall-mount speakers were used.

Code Blue Stations — 28 Units: DSPPA IP emergency call stations (DIP-A7720) were installed at every nursing station in the hospital — 28 stations covering all inpatient wards (Floors 3-9), the ICU, HDU, and emergency department. Each station has a dedicated Code Blue button, clearly labelled in red, covered by a clear protective flip cover to prevent accidental activation. When activated, the Code Blue station sends a priority message directly to the DSPPA server, which immediately interrupts all other audio across all 120 zones and broadcasts the Code Blue announcement — specifying the floor and ward — through every speaker in the building simultaneously. The announcement is automatically repeated three times and continues until cancelled by a supervisor-level station. This process takes less than 2 seconds from button press to announcement commencement — eliminating the operator dependency that had contributed to the delayed Code Blue responses.

Fire Alarm Integration — Automatic Evacuation: The DSPPA server's dry contact relay inputs were connected to the hospital's Siemens Cerberus PRO fire alarm panel's auxiliary relay outputs. When the Cerberus PRO panel enters alarm state, a relay closure triggers the DSPPA server to broadcast the pre-programmed evacuation announcement automatically within 3 seconds — without any human intervention. The evacuation message specifies the evacuation tone, evacuation instructions in both Bangla and English, and staff assembly point directions. The integration was tested with the hospital's fire safety officer and confirmed to trigger and complete the first announcement within 3.8 seconds of alarm activation — well within the hospital's revised 5-second maximum target.

Background Music and Zone Paging: Waiting areas on the ground floor (main reception, outpatient waiting, emergency department waiting) receive continuous background music from a DSPPA M-series media player connected to the IP server — curated playlists in a calm, non-intrusive style appropriate for a healthcare environment. Zone paging for appointment calls (the outpatient department calling individual patients) operates from a DSPPA IP paging console at the OPD reception desk, reaching only the outpatient waiting area zones without broadcasting to clinical areas.