I’ve just deployed 2 Gigaset DECT VOIP base stations; replacing some old DECT handsets connected to “analogue” circuits (actually an ATA connected to the VOIP telephone exchange). There’s a similar system at one of our other sites I administer (much bigger).
These (and the associated handsets) are really good; but they are different from “normal” British phones and American fixed VOIP sets which are usually set up made to exactly emulate an old phone with “overlap dialling”; so if you pick up the handset you hear dial tone and then the DTMF sounds (the handset or ATA acts as the register and collects the digits and when they match the set patterns or a timeout occurs signalls them to the VOIP exchange via SIP which can only accept “en-bloc” dialling (i.e all the numbers sent at once – just like on a GSM)
So with the gigasets and the other German designed DECT kit; if you have not already dialled the number pressing the green button does not return dial tone; just a list of last numbers dialled. if you have dialled a number you then hear a short burst dialtone (but no DTMF relayed) then ringback or whatever other progress tones would be normal.
I think this has also been normal for all phones in Europe on ISDN or connected via a small exchange such as in a business for 20 odd years.
I explained this to all the end users – basically said “these new phones are German designed; so we must use them like the Europeans do. Number first; then press green button”.
And yet this seems to confuse the hell out of all the British staff at work (some reported the phones as “defective; no dial tone”) and one manager (after I’d explained to her how the devices work) stared blankly at me for some seconds waiting for the dial tone; (those staff from mainland Europe seem to work it out straight away 😉 )
I’ve seen Americans claim that “Europeans all have ISDN” which isn’t strictly true – especially in the UK (its too bloody expensive for one thing and a pig to configure); but from looking at European websites it does seem its more common (and/or British folk (even younger people) sometimes seem a bit backward when it comes to telephones – especially that you have to answer them; and actually talk to people 😉 )
