Call Waiting questions

[Dimitris Kogias]

I've thought of some use cases where the exact "API" that the GSM stack
presents to the open part of the phone makes a difference.

Sean, how is call waiting implemented?  Specifically, where is the
"beep" sound one normally hears when there's an incoming call while an
earlier call is in progress generated?  Is it done at the carrier side,
or generated by the GSM chipset?  If the latter, can the chipset on the
Neo be told to suppress it, assuming that the "pure" signaling info (the
incoming caller ID for example) is still available on the UART control
channel?

D.