Customer reports: We have several of our MC5574s at our Alaska location, these users are not on ATT. They are a mix of 6.1 and 6.5 OS. They are having issues when traveling to remote locations where calls can be placed to the device, but the user cannot call out. They spoke with GCI, thier service provider, who said thier system is a tone based system, and the "Connection Tone" or "Call Tone" needs to be set differently. Can this be changed on a MC5574?