Aiphone NHX-50M 50-Call Audio Master Station

Aiphone NHX-50M 50-Call Audio Master Station with Handset

The Aiphone NHX-50M is a 50-call audio master station designed for healthcare and institutional communication systems. This unit serves as the primary control point for managing incoming calls with intelligent priority routing, distinct call signaling, and integrated fault detection. The NHX-50M operates via handset (VOX) or push-to-talk simplex communication, making it suitable for environments requiring flexible operator interaction modes.

Key Features

• Three Call Levels with Distinct Signaling: Manages routine calls, urgent bathroom calls, and cord-out trouble calls with dedicated tone and light signaling to help operators prioritize response.
• Auto-Connect to Next Call: Automatically routes to the next call-in priority without requiring manual station selection, streamlining operator workflow.
• Call-In Priority Queue: Prioritizes calls in order: cord-out trouble calls, urgent bathroom and common area bathroom/staff calls, and routine station calls based on urgency level and time-stamp sequencing.
• LED and Tone Annunciation: Slow or fast flashing LED combined with audible tones provide visual and audio indication of routine and bathroom calls for clear operator awareness.
• Fault Detection and Warning Tones: Sounds fault tone when wires are disconnected or shorted at patient station, or when handset is off-hook for more than 90 seconds; line-off trouble detected at bedside or NHR-3TS stations triggers warning tone at duty station (can be silenced via 2-pin jumper to CN104 in Central Control Unit).
• 90-Second Timer Escalation: Call tone automatically escalates to HIGH level after 90 seconds of elapsed time, alerting operators to aging calls requiring immediate attention.
• Handset VOX and Push-to-Talk Modes: Supports both voice-operated (hands-free) and push-to-talk simplex communication for operational flexibility.
• Compliant Wiring Standard: Connects to Central Control Unit via 5 twisted pair, low capacitance, polyethylene-insulated cable with overall shield (Aiphone #862210 recommended); supports distances up to 65 feet at 22 AWG.

Integration and Compatibility

The NHX-50M integrates with the complete Aiphone NHX system ecosystem. Compatible substations include the NH-1SA/A single-jack bedside audio, NH-2SA/A dual-jack bedside audio, and NHR-3TS dual corridor light stations. The unit requires a Central Control Unit (NHX-80X) and supports system expansion via the NHR-30K 30-call add-on selector for 51–80 station configurations. Duty stations connect via NHR-SP audio modules, while call signaling components include the NHR-7A pull cord and NHR-8A-L bedside call cord. Corridor lighting via NHR-4A/A dual LED lamps provides visual indication of incoming calls throughout the facility.

The NHX-50M (often searched as NHX 50M) operates in simplex communication mode, meaning one-way or alternating two-way audio without simultaneous transmission. This design reduces system complexity and cost while maintaining reliable call delivery and operator acknowledgment in typical institutional settings.

Ted Perry

Perspective based on aggregated IP Security Depot and affiliated engineering team experience.

The Aiphone NHX-50M is a workhorse master station for healthcare facilities and institutional environments where call prioritization and operator efficiency are critical. I've specified this unit in several deployments where managing 50+ bedside and corridor stations required reliable priority queuing and fault detection to maintain patient safety and operational workflow.

Technical Highlights:

• Three-Tier Call Priority: Cord-out trouble calls take absolute priority, followed by urgent bathroom calls, then routine calls—ensuring emergencies reach the operator first regardless of call volume.
• Automatic Call Routing: The auto-connect-to-next-call feature eliminates manual station selection, reducing operator workload and response latency during high-call periods.
• Comprehensive Fault Detection: The 90-second off-hook timer and line-fault detection prevent silent failures; the escalating tone after 90 seconds ensures aging calls are acknowledged even if the operator is distracted.
• Flexible Communication Mode: VOX (voice-operated) handset mode enables hands-free acknowledgment; push-to-talk offers control when operator clarity is essential.

Deployment Considerations:

• Wire runs from master station to Central Control Unit should not exceed 65 feet at 22 AWG using Aiphone #862210 cable; longer runs may require heavier gauge or active drivers depending on system impedance and capacitance limits.
• The 5 twisted-pair cable topology with shield provides adequate noise rejection in typical institutional environments; verify grounding of shield at Central Control Unit to avoid ground loops if multiple grounds are present.
• Fault tone silencing via CN104 jumper should be configured post-deployment to match facility protocols—many operators prefer immediate silence after confirming a line-off fault rather than continuous warning tone.

For facilities with 50–80 stations, pair the NHX-50M with the NHR-30K add-on selector to expand capacity without replacing the master station. The unit's proven reliability and straightforward priority logic make it a dependable choice for mission-critical communication in patient care and emergency response environments.