Any idea why I get a two or three second tone that sounds like a beep for a phone every time I start the car? How do I get rid of this annoyance. Note, I don't have the OEM phone installed in the car.

 

Sounds like your alarm system.

 

If the tone is caused by the alarm is there a way to disable the alarm?

 

I think this is how I turned my alarm off, I don't really remember, if you disconnect the battery for a few minutes then hook back up.
Will also need to re code the stereo.

 

You may well have solved all of your problems by now; however, I have found on my 96 SL500 if the top is not fully seated I will get a loud beep. Found this out when cleaning the rear (plastic) window on the soft top and intentionally stopped mid cycle so I could get to inside of window. I'm too tall and big to get to it inside. When I went to reactivate top after starting the car, got a loud beep and flash of activation button.