I have a Siemens DECT phone, which is touchtone and a Linksys SPA3000. Whenever I call a service that needs you to press certain buttons to get through the automated menus it doesn't register. In that I press the button, I hear a beep but the other end doesn't get anything. In some respects this is good as can jump the cue when calling my bank and straight to customer services However sometimes it would be useful, is this a setting on the SPA3000 or a limitation of VOIP ? tia

VoIP can carry DTMF tones. The problem is that with SIP there are 3 ways of doing it- in-band (i.e. same as analogue as part of the voice channel), SIP INFO and AVT. On Linksys/Sipura phones, this is controlled by the 'DTMF Tx Method' setting (one for each line). Try changing the setting from the default 'auto', it depends on the provider e.g. sipgate uses SIP INFO.