I don't think this is possible, but I certainly agree it should be. At this time there no way to use RingCentral to call an IVR that requires to use a leading "*", for example. There should be an escape code to override RC from listening for codes. Or a code to disable for the duration of a call. Something like dial *#* and then all tones are passed to the other end of the call and ignored by Ringcentral.