| Power Source | 
230 V AC, 50/60 Hz (supplied AC adapter must be used) | 
| Power Consumption | 
8 W (based on UL standards) Max. 40.8 W (rated output at IR-820SP) | 
| Receiving Frequency | 
Teacher (Channel A): 3.100 MHz Student (Channel B): 3.350 MHz | 
| Receiver Sensitivity | 
50 dB or more, Signal to Noise ratio (40 dBμV input, 1 kHz modulation, ±4.8 kHz deviation) | 
| Signal to Noise Ratio | 
Tuner: 60 dB or more (60 dBμV input, 1 kHz modulation, ±4.8 kHz deviation, A-weighted, Equalization: Centered) AUX: 75 dB or more (A-weighted, Equalization: Centered) | 
| Tone Squelch Frequency | 
32.768 kHz | 
| Input | 
AUX PC: line, -10 dB*, 10 kΩ, unbalanced, stereo mini jack (internal mixing) AUX DVD/TV: line, -10 dB*, 10 kΩ, unbalanced, 2P RCA jack (internal mixing) AUX MP3: line, -10 dB*, 10 kΩ, unbalanced, stereo mini jack (internal mixing) Mute: 25 V line signals of telephone paging from a school intercom system | 
| Output | 
ALD (Assistive Listening Device): line, -10 dB*, 10 kΩ, unbalanced, monaural mini jack Speaker: RJ45 (dedicated terminal for IR-820SP connection) | 
| Frequency Response | 
Tuner: 100 Hz - 12 kHz, AUX: 100 Hz - 20 kHz | 
| Equalization | 
High: ±10 dB at 10 kHz Mid: ±10 dB at 1.3 kHz Low: ±10 dB at 100 Hz | 
| Mute Function | 
Muted by 25 V line signals | 
| LED Indicator | 
Power (green) × 1, Infrared Reception (yellow) × 2, Mute (red) × 1 | 
| Operating Temperature | 
-10 ℃ to +50 ℃ (14 ゜F to 122 ゜F) | 
| Operating Humidity | 
90 %RH or less (no condensation) | 
| Finish | 
Panel: Aluminum, black Case: Steel plate, black | 
| Dimensions | 
210 (W) × 46 (H) × 312 (D) mm (8.27 × 1.81" × 12.28") | 
| Weight | 
1.8 kg (3.97 lb) | 
| Accessory | 
AC adapter (DC cord length: 1.8 m (5.91 ft)) …1, AC power cord (2m (6.56 ft)) …1, Volume control cover …6, Removable terminal plug (2 pins) …1 | 
| Option | 
Half width blank panel: MB-15B-BK |