A vonage question

Hi all,

Not sure if anyone can help with this, but sometimes when we put down
the phone connected to our Linksys ATA, the phone will give a short
ring tone. I pick up the phone around 30 seconds later, to find no
dial tone. There is no call made out out other than to the last
dialed number. I can reset this by pressing the hang up button on the
handset.

Any suggestions?
Andrew.
--
Andrew Hodgson in Bromyard, Herefordshire, UK.
My Email: use <andrew at hodgsonfamily dot org>.