Atcom has today 2nd July 2009 released a new firmware for their Atcom AT510  and AT510P phones. The firmware fixes a recently discovered bug where if using the IAX protocol calls placed on hold are dropped. The firmware will appear soon on the Atcom website but can also be downloaded here.

http://www.ipchitchat.co.uk/index.php/View-details/Atcom-Firmware/23-Atcom-AT510-Firmware