I have a customer with a km 2050 and KM 1820 who send faxes to another company who's fax line has voicemail on it at well. some of the voicemails seem to be very long winded per se and the machine is ending the call before their machine picks up for the tones. Is there a Sim or something to extend how long a machine will continue sending out the tones till their machine picks up?