chan_ss7 variables:
===================

variables read by chan_ss7:
---------------------------
  ISDN_H324M: If this variable is set, then chan_ss7 signals 
              H324M (3G Video aka H.223 and H.245) in outgoing IAM
              messages. Allowed values (case sensitive):
                USI	signal H324M in User Service Information field
                LLC	signal H324M in Access Transport field using Low
			Layer Compatibility
                USI+LLC	signal H324M in User Service Information field AND
			Access Transport

              Note: chan_ss7 read the variable from the outgoing channel. As in 
              extensions.conf only the incoming channel variables can be set, you
              have to set the variable as a global variable by prefixing with __ 
              (double underscore). Usage example:

		[from-sip-phone]
		exten => _videoX.,1,h324m_call(${EXTEN}@tomobile)
		[tomobile]
		exten => _videoX.,1,Set(CALLERID(num)=0043123456)
		exten => _videoX.,n,Set(__ISDN_H324M=USI+LLC)
		exten => _videoX.,n,Dial(ss7/siuc/${EXTEN:5}|90|)




variables set by chan_ss7:
--------------------------
  none (there should be a variable which indicates if the incoming call
  is a H324M video call, but this is not implemented yet)