looks like i have the answer (painfully newbish 
, but still going to share it, hopefully it helps sbd ) => never used the phone before (it’s siemens gigaset a160) and just found out that it is its nature (no dialtone unless dialing). always test your phone in normal pstn first (if you have one 
) . different phone works exactly the way I expected.
i guess the whole confusion came from the fact that gigaset did not sent offhook signal till dialing, that’s why this message is displayed so late under asterisk: – Starting simple switch on ‘Zap/1-1’, and with normal you see it straight after pressing dial.