The I2C-RELAY16 is an I2C daughterboard providing 16 output channels, designed to piggyback on commonly available Chinese-made boards with 16 SPDT relays. (We don't sell the relay boards directly, but they're available from multiple sources - various vendors on Amazon (#1, #2), SainSmart, or even direct from China on eBay.)
The board includes two ISE Standard I2C 6P6C Connectors, a female 20-pin dual row connector to attach to the relay board's header, a PCA9671 I2C 16 channel I/O expander, and three address jumpers to select 1 of 8 possible addresses. The standard ISE I2C connector makes it easy to add the I2C-RELAY16 to our I2C products with integrated microcontrollers, such as the MRB-IAS MRBus I2C Awesome Stick or the MRB-ARD MRBus Arduino Shield. For Arduino users, be sure to check out the "Documentation" tab for a link to our Relay16 library and example sketch.
The I2C connection follows the ISE I2C 6P6C Connector Standard.