[Asterisk-Users] Calling Party ringing indicator

[John Zielinski]

I am new to Asterisk and I'm setting up my first Asterisk box.  When 
recieving inbound SIP calls from sipphone.com my friends would not get 
the ringing indicator after I did an answer command.   I found that 
after playing a gsm file first the ringing started to work like it did 
for my pots incoming calls.  I created a short virtually silent gsm file 
and that worked as well if played before the dial command.  Just 
wondering why SIP works this way and if there is a better solution.  
BTW, I'm not using the "r" parameter to the dial command.

John