Communication between an image forming device and a replaceable supply item

A method of facilitating electrical communication between a controller of an image forming device and a chip for use on a replaceable supply item of the image forming device, comprising:

• configuring the chip to operate as a slave node on an I2C communication bus where the controller of the image forming device serves as a master node on the I2C communication bus;
• configuring the chip to receive a first write command from the controller of the image forming device, to determine whether a transmission cycle bit of the first write command matches a transmission cycle bit of a second write command received by the chip from the controller of the image forming device previous to the first write command, and to resend to the controller of the image forming device a response to the second write command if the transmission cycle bit of the first write command matches the transmission cycle bit of the second write command;
• and
• configuring the chip to determine whether a command ID of the first write command matches a command ID of the second write command if the transmission cycle bit of the first write command matches the transmission cycle bit of the second write command and to perform said resend to the controller of the image forming device the response to the second write command if the command ID of the first write command matches the command ID of the second write command.