To answer your question.....I don't know.
BUT if at home you could do this:
Set up a voip.ms account.
Get a voip number of your choice. (called a DID) cost is 85 cents a month US$
See current charges per minute for inbound outbound calls at voip.ms
Hardwire your ATA box to your router by ethernet
Have a wireless land line hand set, like Panasonic LinkToCell or any other Panasonic
Hardwire the main set to the ATA box by a 2 wire phone cable.
While in service put your PM phone on call forward to your voip.ms number.
All inbound calls to your PM number will now ring on your voip phone at home.
For making outbound calls from your voip account, set up your DID account to show your caller ID as your PM number.
voip.ms is in US$ and when we used as a land line the cost was about $12-$13 a month, but likely would be less for you.
PM me for more info if you like.