The "S661" refers primarily to the , a popular pair of bone-conduction headphones often categorized as a wearable audio controller for sports and lifestyle use. There is also a industrial Simpson S661 Rate Counter , which acts as a digital controller for industrial pulse counting.
: With power off, hold Volume+ for 5s until the LED flashes red/blue. 2. Using the Multifunction Button (Left Side) Controls media and calls: Play/Pause/Answer/End Call : Click once. Skip/Previous Track : Double/Triple-click during playback. Voice Assistant : Hold for 2s while in standby. 3. Advanced Audio & Maintenance s661 controller manual exclusive
: Compatible with pulses up to 30 kHz (Quadrature, TTL, NPN/PNP). Shokz S661 (Consumer) Simpson S661 (Industrial) Category Bone Conduction Audio Digital Rate Counter/Controller Power USB-C Rechargeable 120/240 VAC Line Power Control Interface Physical Buttons / Voice Prompts Front Panel Buttons / EEPROM Primary Use Sports & Communication Pulse Counting & Industrial Monitoring The "S661" refers primarily to the , a