A method and apparatus for interrupt signaling. A communication network is described comprising a master device and a slave device that are both coupled to a two wire serial bus for communication. The two wire serial bus comprises a serial data (SDA) line and a serial clock line. The master device controls communication between the master device and the slave device. The slave device is capable of generating an interrupt signal during an idle condition over the SDA line for requesting a communication transaction with the master device. Also, a method is described for recognizing an interrupt at the master device. During an idle condition over the SDA line, the master device reads the SDA line low. Previously, the slave device pulls the SDA line low during the idle condition. The master device recognizes the reading of the SDA line low as an interrupt signal from the slave device requesting the communication transaction.