Retevis RT-9908 Dual-Way Window Intercom System for Bank Counter Interphone Features: - Automatic dual-way intercommunication without pressing any button - Anti-interference and noise-free operation - Dual-way audio recording output - Compatible with 110 V and 220 V power supply - All items are - Two-way voice intercom technology with automatic speech signal processing during calls - Dedicated anti-side tone processing chip with auto-mute function - Fully automated call control - Integrated microphone and speaker design for easy installation - High-performance electro-acoustic circuit design with 3W output power for clear, loud, and distinct audio - Two-way voice signal output (for recording by bank teller) via stereo jack - Voice recording function controlled by power switch Applications: Banks, securities offices, bus stations Specifications: - Working voltage: AC 12 V / 1 A - Main sound (sub sound) output: 3 W / 3 W - Frequency response: 100 Hz – 15 kHz - Inside microphone sensitivity: –38 dB ±2 dB, frequency range: 20 Hz – 16 kHz - Outside microphone sensitivity: –38 dB ±2 dB, frequency range: 20 Hz – 20 kHz - Dimensions: 158 × 87 × 46 mm Package Includes: - 1 × Dual-way counter interphone - 1 × External speaker - 1 × Charger - 1 × English user manual