Gsm gateway (set as extension) is not sending dial tones to transfer calls, blind transfer. or dial options in pbx

gsm gateway (set as extension) is not sending dial tones to transfer calls, blind transfer. or dial options in pbx

that trunk is set to work with alaw and ulaw.
the polycom can succesful transfer. blind transfer or dial options in pbx or ivr. but the gsm extension ( cellular can not. what I need to do in order to allow that gsm extension celullar to allow send tones ???