Specifications: Model: AD22A08 Working Voltage: DC 12V Size: 94*62*18mm/3.7*2.44*0.7in Maximum Load: 10A/250VAC, 10A/125VAC, 10A/30VDC, 10A/28VDC, 10A/12VDC Instructions: You need two phones, one as a receiver (phone_1), the other one as a transmitter (phone_2); mobile phone_1 connected by DTMF audio cable 3.5MM audio controller (the controller to be powered), and then using phone_2 ( may be a fixed telephone) call the phone_1, phone_1 answered, so that two phone call each other; then dial 1/2/3/4/5/6/7/8 by phone_2 keypad to control 8 relays . Caution: 1. DTMF audio controller must use stable work of DC 12V power supply (recommendations 2A or above the power adapter) 2. Remote control the controller by a mobile phone, the receiver must be the phone with 3.5MM audio interface, the transmitter can be a cell phone or landline 3. As a receiver of the phone must output a sound (not muted), or they will not control relays. Glossary: NO: Normal open COM: Common terminal NC: Normal Connect Relay open: COM connected NO but disconnected NC Relay close: COM disconnected NO but NC connected COM. Non-locking (Momentary ): Dial 1 (2/3/4 is the same), relay 1 "Open", relay close after 1 second delay Self-locking: Dial 1, relay 1 "Open", dial 1 again, relay 1 "off", and so on Inter-lock: Dial 1, relay 1 "Open", other relays "Off"; dial 2, relay 2 "Open", other relays "off", and so on "Delay": Dial 1, relay 1 "Open", relay 1 "Close" after a time Package Includes: 1 x Relay Module 1 x 3.5mm Audio Cable