In the end you have to consider that the idea of a connection
in a communication entails "routing" an incoming signal and
redirecting it to another device. In any such system there
is an address that will instruct switches to set up two data
streams, the streams may be combined into one path and then
decomposed back into two distinct data streams somewhere
later down the line.
in todays modern language the soft switch is called a gateway
which is basically a computer server. Features like call
waiting are part of a feature server. It will handle holding
the call sending a (an audible) signal to the handset piggy
backing the tone or command on the back of the pre existing
incoming signal.
The part above where the data is combined is handled by
a program and that program can be modified not only to allow
the piggy back signal but to take an outgoing command
from the handset which then goes back to the features
server which then commands the soft switch / gateway to
switch to the waiting call. One target for a simple proof
of concept test would be to set up a subroutine in the
features server to accept another call from the handset as
call waiting to the receiving call except instead of sending
a signal to the receiving handset user, the signal is used
by the features gateway to switch to the other mode.
In this case the phone would search for a wifi signal and
then if found attempt to establish a connection which then
would allow it to contact the features gateway. Of course
there would have to be a reformulation of the data so once
the features server initiated the switch the streams would
be compatible.
for tmobile to make a full blown test they would need to have
at the very least access to the features server of their
prefered carrier affiliate, since tmobile phones have had
call waiting for i'd say on the order of a decade this needed
technology would have been available to tmobile engineers.
in fact one would invision a big box with lots of wires that
would be hooked into a local internet connection and then
wired into a selected port of the media gateway dedicated to
the features server.
Imho, leon had such a box, clunky im sure it was w/ lots of
wires
folks, this is what is called a prototype
p2k
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