Mobile devices use a PBX and application servers associated with the PBX to access voice services. Some mobile devices can support simultaneous data and voice channels, with the PBX and application server respectively. Where a data channel is unavailable, a control and status updating mechanism is needed. One approach is to signal over the voice channel with DTMF tones. DTMF tones should be timed to cause the tones to arrive at the mobile device during a pause period of a ring cycle. However, it also is desirable to avoid unnaturally long silence periods or other pauses during system usage. Aspects relate to enhancing a user experience in these situations and successful transmission/reception of control and status information over a voice channel using DTMF tones.